Problem:
 Score : 100 points    Problem Statement There is a right triangle ABC with ∠ABC=90° .  Given the lengths of the three sides, |AB|,|BC| and |CA| , find the area of the right triangle ABC .  It is guaranteed that the area of the triangle ABC is an integer.      Constraints  1 \leq |AB|,|BC|,|CA| \leq 100  All values in input are integers.  The area of the triangle ABC is an integer.         Input Input is given from Standard Input in the following format:  |AB|  |BC|  |CA|       Output Print the area of the triangle ABC .        Sample Input 1 3 4 5      Sample Output 1 6   This triangle has an area of 6 .       Sample Input 2 5 12 13      Sample Output 2 30  This triangle has an area of 30 .       Sample Input 3 45 28 53      Sample Output 3 630  This triangle has an area of 630 .

Solution (Python):
tri = list(map(int, input().split(' ')))
print(tri[0] * tri[1] // 2)

Solution (Python):



AB, BC, CA = map(int, input().split())





print(int(BC * AB / 2))

Solution (Python):
a,b,c = map(int, input().split())

print(int(a*b*0.5))

Solution (Python):
ab,bc,ca=map(int,input().split())
print(int(ab*bc*0.5))

Solution (Python):
a,b,c=map(int,input().split());print(a*b//2)

Solution (Python):
a=list(map(int,input().split()))
print(a[0]*a[1]//2)

Solution (Python):
a, b, x = map(int, input().split(" "))
print((a * b) // 2)

Solution (Python):
x = list(map(int,input().split()))
print(int(sorted(x)[0]*sorted(x)[1]/2))

Solution (Python):
A, B, C = map(int, input().split())
print(int(A*B/2))

Solution (Python):
a = list(map(int,input().split()))
print(int(a[0]*a[1]/2))

Solution (Python):
a,b,c =sorted(map(int,input().split()))
print((a*b)//2)

Solution (Python):
l = [int(i) for i in input().split(" ")]
print(int((l[0]*l[1])/2))

Solution (Python):
l = list(map(int, input().split()))

l.sort

print(int(l[0]*l[1]/2))

Solution (Python):
l = [int(i) for i in input().split()]

print(int(l[0]*l[1]/2))

Solution (Python):
l = list(map(int,input().split()))
print(l[0]*l[1]//2)

Solution (Python):
h, w, _ = map(int, input().split())
print(w * h // 2)

Solution (Python):
a,b,c=map(int,input().split())
print(int(min(a*b,b*c,c*a)/2))

Solution (Python):
a,b,c = map(int,input().split())
print((a*b)//2)

Solution (Python):

a,b,_=map(int,input().split())
print(a*b//2)

Solution (Python):
a = list(map(int,input().split()))
a = sorted(a)
print(int(a[0]*a[1]/2))

Solution (Python):
a,b,c = map(int,input().split())
print((a*b)//2)

Solution (Python):
AB, BC, CA = map(int, input().split())
print(int(AB * BC / 2))

Solution (Python):
a,b,c=map(int,input().split())
print(a*b//2)

Solution (Python):
A, B, C = map(int, input().split())
T = (A + B + C) / 2
S = (T * (T - A) * (T - B) * (T - C)) ** (1/2)

print(int(S))

Solution (Python):
a, b, c = map(int, input().split())
print(a * b // 2)

Solution (Python):
a,b,c = map(int, input().split())
print(a * b // 2)

Solution (Python):
ab, bc, ca = map(int, input().split())
print(ab*bc//2)

Solution (Python):
AB,BC,CA = list(map(int,input().split()))
print(AB*BC//2)

Solution (Python):


def main():

    A,B,_=map(int,input().split())
    print(int(A*B/2))



if __name__== "__main__":
    main()

Solution (Python):
import math
inp = input().split()

ab = int(inp[0])
bc = int(inp[1])
ca = int(inp[2])

print(math.ceil(0.5*ab*bc))

Solution (Python):
x,y,z = map(int,input().split())
print(int((x*y)/2))

Solution (Python):
a,b,c=map(int,input().split())

print(int(a*b/2))

Solution (Python):
a, b, c = map(int, input().split())
print(a * b // 2)

Solution (Python):
ab,bc,ca=map(int,input().split())
print(ab*bc//2)

Solution (Python):
ab, bc, ca = map( int, input().split() )

print( int( ab*bc/2 ) )

Solution (Python):
l = list(map(int, input().split()))
l.sort()
print(l[0] * l[1] //2 )

Solution (Python):
AB,BC,CA = map(int,input().split())
print(int(AB*BC/2))

Solution (Python):
ab,bc,ca = map(int, input().split())
print(int(ab * bc * 1/2))

Solution (Python):
ab, bc, ca = map(int, input().split())

print(int(ab * bc / 2))

Solution (Python):



l = list(map(int, input().split()))


l.sort()
ans = int(l[0] * l[1] / 2)


print(ans)

Solution (Python):
a,b,c = map(int,input().split())
print(round(a*b/2))

Solution (Python):
a,b,c = list(map(int,input().split()))
print(a*b*1//2)

Solution (Python):
li = list(map(int, input().split()))

li.sort()

print(int(li[0] * li[1] / 2))

Solution (Python):
a,b,c = sorted(map(int, input().split()))
print(int(a*b/2))

Solution (Python):
x,y,_=map(int,input().split())
print(x*y//2)

Solution (Python):
a,b,c = map(int,input().split())
print(a*b//2)

Solution (Python):
x,y,z=map(int,input().split())
print(x*y//2)

Solution (Python):
ab,bc,ca=map(int,input().split())
print(int(ab*bc*(1/2)))

Solution (Python):
a, b, c = map(int, input().split())
print(a*b // 2)

Solution (Python):
a, b, c = map(int, input().split())
print(a * b // 2)

Solution (Python):
A, B, C = map(int, input().split())
print((A*B)//2)

Solution (Python):
x,y,z = map(int,input().split())

print( int(x * y / 2) )

Solution (Python):
def main():
    c, a, b = map(int, input().split())
    m = max(a, b, c)
    if a == m:
        print(b * c // 2)
    elif b == m:
        print(a * c // 2)
    else:
        print(a * b // 2)


main()

Solution (Python):

from collections import defaultdict
from collections import deque
from heapq import heappush, heappop
import sys
import math
import bisect
import random
import itertools
sys.setrecursionlimit(10**5)
stdin = sys.stdin
bisect_left = bisect.bisect_left
bisect_right = bisect.bisect_right
def LI(): return list(map(int, stdin.readline().split()))
def LF(): return list(map(float, stdin.readline().split()))
def LI_(): return list(map(lambda x: int(x)-1, stdin.readline().split()))
def II(): return int(stdin.readline())
def IF(): return float(stdin.readline())
def LS(): return list(map(list, stdin.readline().split()))
def S(): return list(stdin.readline().rstrip())
def IR(n): return [II() for _ in range(n)]
def LIR(n): return [LI() for _ in range(n)]
def FR(n): return [IF() for _ in range(n)]
def LFR(n): return [LI() for _ in range(n)]
def LIR_(n): return [LI_() for _ in range(n)]
def SR(n): return [S() for _ in range(n)]
def LSR(n): return [LS() for _ in range(n)]
mod = 1000000007
inf = float('INF')


def A():
    a = LI()
    a.sort()
    print(a[0]*a[1]//2)  
    return


def B():
    return


def C():
    return


def D():
    return


def E():
    return


def F():
    return


def G():
    return


def H():
    return


if __name__ == '__main__':
    A()

Solution (Python):
a,b,c = map(int,input().split())
print(a*b // 2)

Solution (Python):
AB, BC, CA = map(int, input().split())
print(int(AB * BC / 2))

Solution (Python):
edges = list(map(int, input().split()))
edges.sort()
print((edges[0]*edges[1])//2)

Solution (Python):


C,A,B = [int(i) for i in input().split()]
X = (C * A) /2
print(int(X))

Solution (Python):
a,b,c=map(int,input().split())
print(a*b//2)

Solution (Python):
N=list(map(int,input().split()))
d=sorted(N)
print(int(N[0]*N[1]/2))

Solution (Python):
a,b,c = list(map(int, input().split()))

if a == max(a, b, c):
	print(b*c//2)
if b == max(a, b, c):
	print(c*a//2)
if c == max(a, b, c):
	print(a*b//2)

Solution (Python):
a, b, c = map(int, input().split())
print(int((a*b)/2))

Solution (Python):
a, b, c = map(int, input().split())
print(a * b  // 2)

Solution (Python):
l = sorted(list(map(int, input().split())))
print(l[0]*l[1]//2)

Solution (Python):
a, b, c = map(int, input().split())
print(a * b // 2)

Solution (Python):
l = list(map(int, input().split()))
l.sort()
print(l[0] * l[1] // 2)

Solution (Python):
ab, bc, ca = map(int, input().split(' '))
print(ab * bc // 2)

Solution (Python):



a,b,c = map(int,input().split())
print(a*b//2)

Solution (Python):
a, b, c = (map(int, input().split()))
print(int(a * b / 2))

Solution (Python):
A, B, C = map(int, input().split()) 
print(int(A*B/2))

Solution (Python):
a,b,c = map(int,input().split())
x = max(a,b,c)

ans = (a*b*c)//(x*2)
print(ans)

Solution (Python):
import math

l = list(map(int, input().split()))

s = sum(l)/2

ans = int(math.sqrt(s * (s - l[0]) * (s - l[1]) * (s - l[2])))
print(ans)

Solution (Python):
a, b, c = map(int, input().split())
print(a * b // 2)

Solution (Python):
a,b,c=map(int,input().split())
print(a*b//2)

Solution (Python):
A, B, C = map(int, input().split())
print(A*B//2)

Solution (Python):
AB, BC, CA = map(int,input().split())
print(int(AB*BC/2))

Solution (Python):
ab,bc,ca = map(int,input().split())
print(ab*bc//2)

Solution (Python):
ab, bc, ca = map(int,input().split())
print(ab * bc // 2)

Solution (Python):
ab, bc, ca = map(int, input().split())
print(ab * bc // 2)

Solution (Python):
hs = list(map(int, input().split()))
hs.sort()
print(hs[0] * hs[1] // 2)

Solution (Python):
l=[]
l=input().split(" ")
a = int(l[0])
b = int(l[1])
print((a*b)//2)

Solution (Python):
X,Y,Z=map(int,input().split())
if (X>Y) and (X>Z):
  print(int(Y*Z/2))
elif (Y>X) and (Y>Z):
  print(int(X*Z/2))
else:
  print(int(X*Y/2))

Solution (Python):
A,B,C = map(int,(input().split(" ")))

print(int((A*B)/2))

Solution (Python):
ab,bc,ca = map(int,input().split(' '))

print(int(ab * bc /2))

Solution (Python):
ab,bc,ca=map(int,input().split())
print(ab*bc//2)

Solution (Python):
a, b, c = map(int, input().split())
print(a * b // 2)

Solution (Python):
import math

AB, BC, CA = map(int, input().split())
s = (AB + BC + CA) / 2

print(int(math.sqrt(s* (s - AB) * (s - BC) * (s - CA))))

Solution (Python):
print(eval("*".join(input().split()[:2]))//2)

Solution (Python):
a, b, c = list(map(int, input().split()))
print(a*b//2)

Solution (Python):
a = list(map(int,input().split()))
print(int(0.5*a[0]*a[1]))

Solution (Python):
a,b,c=map(int,input().split())
print(int(a*b/2))

Solution (Python):
a,b,c = map(int,input().split(" "))
d = max(a,b,c)
prod = a*b*c//(d*2)
print(prod)

Solution (Python):
A,B,C=map(int,input().split())

print(int(A*B/2))

Solution (Python):
a,b,c = map(int,input().split())
print(a*b//2)

Solution (Python):
a,b,c = map(int,input().split())
print(int(a*b/2))

Solution (Python):
a, b, c = map(int, input().split())
print(a * b // 2)

Solution (Python):
a, b, c = map(int, input().split()); print(round((a*b)/2))

Solution (Python):
n1, n2, n3  = [int(i) for i in input().split()]

r1 = (n1 * n2) / 2

print(int(r1))

Solution (Python):
c,a,b=map(int,input().split())
print(c*a//2)

Solution (Python):
ABC = list(map(int, input().split()))
ABC.sort()
print("{:.0f}".format(ABC[0] * ABC[1] / 2))

Solution (Python):
a, b, c = map(int, input().split())

print((a*b)//2)

Solution (Python):
a = list(map(int, input().split()))
a.sort()
print(a[0]*a[1]//2)

Solution (Python):
AB, BC, CA = map(int, input().split())

ans = AB * BC // 2
print(ans)

Solution (Python):
A,B,C=map(int,input().split())
print(A*B*C//(2*max(A,B,C)))

Solution (Python):
AB,BC,CA = map(int,input().split())
print(int((AB*BC)/2))

Solution (Python):
a=list(map(int,input().split()))
print(int(a[0]*a[1]/2))

Solution (Python):
nl = lambda: list(map(int, input().split()))
sl = lambda: input().split()
n = lambda: int(input())
s = lambda: input()

AB, BC, CA = nl()

print(AB*BC // 2)

Solution (Python):
AB, BC, CA =map(int, input().split())
print(int(AB*BC/2))

Solution (Python):
A, B, C = map(int, input().split())

if max(A, max(B, C))==A:
    print(int(B*C*0.5))
elif max(A, max(B, C))==B:
    print(int(A*C*0.5))
else:
    print(int(A*B*0.5))

Solution (Python):
a = list(map(int, input().split()))
a.sort()
print(a[0]*a[1]//2)

Solution (Python):
a,b,c=map(int,input().split())
print(int(a*b*0.5))

Solution (Python):
a,b,c = map(int,input().split())
print(a*b//2)

Solution (Python):
a,b,c = map(int,input().split(' '))
S = (a*b)//2
print(S)

Solution (Python):
a, b, c = map(int, input().split())
print(a*b//2)

Solution (Python):
c,a,b = map(int,input().split())
print(int(c*a/2))

Solution (Python):
ab,bc,ca=map(int,input().split())
print(ab * bc // 2)

Solution (Python):
a,b,c=map(int,input().split())
print(a*b//2)

Solution (Python):
c=list(map(int, input().split()))

c.remove(max(c))

print(int((c[0]*c[1])/2))

Solution (Python):
ab, bc, ca = map(int, input().split())

print(int(ab * bc / 2))

Solution (Python):
A, B, C = map(int, input().split())
print(A * B // 2)

Solution (Python):
A,B,C = input().split()

print(int(A)*int(B)//2)

Solution (Python):
a, b, c = map(int, input().split())
print(a * b // 2)

Solution (Python):
a, b, c = map(int, input().split())
print(a * b // 2)

Solution (Python):
l = list(map(int, input().split()))
l.sort()
print(int(l[0]*l[1]*0.5))

Solution (Python):
A,B,C = map(int, input().split())
print(int(A*B / 2))

Solution (Python):
a, b, c = map(int, input().split())
print(a*b//2)

Solution (Python):
a,b,c=map(int, input().split())
ans=a*b/2
print(int(ans))

Solution (Python):
ab, bc, ca = map(int, input().split())
print(int(ab * bc / 2))

Solution (Python):
A,B,C=map(int, input().split())
print(A*B//2)

Solution (Python):
a = list(map(int, input().split()))
a.sort()
print(int(a[0] * a[1] / 2))

Solution (Python):
import math
sa = list(map(int,input().split(' ')))



s = (sa[0]+sa[1]+sa[2])//2
ans = int(math.sqrt(s*(s-sa[0])*(s-sa[1])*(s-sa[2])))
print(ans)

Solution (Python):
AB,BC,CA=list(map(int,input().split()))

answer=AB*BC//2

print(answer)

Solution (Python):
a, b, c = map(int, input().split())
print((a * b) // 2)

Solution (Python):
A, B, C = map(int, input().split())
print(int((A * B) / 2))

Solution (Python):
AB, BC, CA = map(int, input().split())

S = int(AB*BC*0.5)
print(S)

Solution (Python):
a, b, c = map(int, input().split())
print(int(a * b / 2))

Solution (Python):
AB, BC, CA = map(int, input().split())

print(int(AB * BC / 2))

Solution (Python):
a = list(map(int,input().split()))
a.sort()
print(a[0]*a[1]//2)

Solution (Python):
ab,bc,ca=map(int,input().split())
print(int(ab*bc/2))

Solution (Python):
a,b,c = map(int,input().split())
print(int(a*b/2))

Solution (Python):



import sys

input = sys.stdin.readline

def main():
    A = list(map(int, input().split()))
    print(int(A[0] * A[1] / 2))


main()

Solution (Python):
X, Y, Z = map(int, input().split())

print(int(X*Y/2))

Solution (Python):
ab, bc, ca = map(int, input().split())
print(ab * bc // 2)

Solution (Python):
AB, BC, CA = map(int, input().split())
print(int(AB*BC/2))

Solution (Python):
A,B,_=map(int,input().split())
print(A*B//2)

Solution (Python):
def abc():
    ab, bc, ca = map(int, input().rstrip().split())
    print(int(ab * bc / 2))


abc()

Solution (Python):
A,B,C=(int(i) for i in input().split())
print(int(A*B/2))

Solution (Python):
import sys

input = sys.stdin.readline

c, a, b = map(int, input().split())

print(int(0.5*c*a))

Solution (Python):
a, b, c = map(int, input().split())

print(int(a*b/2))

Solution (Python):
a,b,c =sorted(map(int,input().split()))
print(a*b//2)

Solution (Python):
li = list(map(int,input().split()))
A =li[0]
B = li[1]
print(int(A * B / 2))

Solution (Python):
a, b, c = map(int, input().split())
print(a * b // 2)

Solution (Python):
ab , bc , ca = map(int,input().split())

print(int(ab * bc / 2))

Solution (Python):
a=list(map(int,input().split()))
a.sort()
print(a[0]*a[1]//2)

Solution (Python):
a = list(map(int, input().split())) 
a.sort()
print (int(a[0] * a[1] / 2))

Solution (Python):
def resolve():
	a,b,c=map(int,input().split())
	s=(a+b+c)//2
	print(int((s*(s-a)*(s-b)*(s-c))**0.5))
resolve()

Solution (Python):
l = list(map(int, input().split()))

print(int(l[0]*l[1]/2))

Solution (Python):
a, b, c = map(int, input().split())

if a > b and a > c:
  print(b * c // 2)
elif b > a and b > c:
  print(a * c // 2)
else:
  print(a * b // 2)

Solution (Python):
x=list(map(int,input().split()))
x.sort()
print(int(x[0]*x[1]/2))

Solution (Python):
lst = input().split()

print((int(lst[0])*int(lst[1]))//2 )

Solution (Python):
L=list(map(int,input().split()))
L.sort()
ans=L[0]*L[1]/2
print(int(ans))

Solution (Python):
AB, BC, CA = map(int, input().split())
print(int(BC * AB / 2))

Solution (Python):
AB, BC, CA = input().split()
print(int(int(AB) * int(BC) / 2))

Solution (Python):
c, a, b = map(int, input().split())

print(int(c*a/2))

Solution (Python):
A,B,C = map(int, input().split())
print(int(A*B/2))

Solution (Python):
a, b, c = map(int, input().split(" "))
print(int(a * b / 2))

Solution (Python):
a,b,c = map(int,input().split())
print(int(a*b/2))

Solution (Python):
lens = list(map(int, input().split()))
lens.remove(max(lens))
print(lens[0] * lens[1] // 2)

Solution (Python):
a, b, c = map(int, input().split())
print(a*b//2)

Solution (Python):


x,y,z = list(map(int,input().split(" ")))
print(int(y*x*0.5))

Solution (Python):
a,b,c=map(int,input().split())
print((a*b)//2)

Solution (Python):


ab, bc, ca = map(int, input().split(' '))

print(int(ab*bc/2))

Solution (Python):
a,b,c = map(int,input().split())
print(int(a*b/2))

Solution (Python):
li=list(map(int,input().split()))
s=sum(li)
t=min(li)
l=s-t-max(li)
print(t*l//2)

Solution (Python):
A, B, C = map(int, input().split())
print(A*B//2)

Solution (Python):
A=list(map(int,input().split()))
A.sort()
ans=int(A[0]*A[1]/2)
print(ans)

Solution (Python):
a,b,_ = map(int,input().split())
answer = a*b//2
print(answer)

Solution (Python):
A = list(map(int,input().split()))

A.remove(max(A))

print((A[0]*A[1])//2)

Solution (Python):
[a,b,c]=map(int, input().split())
if a > b and a > c:
  print(b * c // 2)
elif b > a and b > c:
  print(a * c // 2)
else:
  print(a * b // 2)

Solution (Python):
a,b,c = map(int,input().split())
print(int(a*b/2))

Solution (Python):
AB, BC, CA = map(int, input().split())
print(int(AB*BC/2))

Solution (Python):
A, B, C = map(int, input().split())
print(A*B//2)

Solution (Python):
c,a,b = map(int,input().split())

print(int(c*a/2))

Solution (Python):
a = list(map(int, input().split()))
a.sort()
print(int(a[0]*a[1]/2))

Solution (Python):
a,b,c = map(int, input().split())
print(a*b//2)

Solution (Python):
c,a,b=map(int,input().split())
print(c*a//2)

Solution (Python):
a,b,c=map(int,input().split())

print(int((a*b)/2))

Solution (Python):
A, B, C = [int(x) for x in input().split()]
A, B = sorted([A, B, C])[:2]
print((A*B)//2)

Solution (Python):
from sys import stdin
A = [int(x) for x in stdin.readline().rstrip().split()]
A.sort()
print(int(A[0] * A[1] / 2))

Solution (Python):
A, B, C = map(int, input().split())
three = [A, B, C]
a = three.pop(three.index(min(three)))
b = three.pop(three.index(min(three)))
print(int(a*b/2))

Solution (Python):
AB, BC, CA = map(int, input().split())
print(int(AB*BC/2))

Solution (Python):
AB,BC,CA=map(int,input().split())
s=int(AB*BC/2)
print(s)

Solution (Python):
a, b, c = [ int(v) for v in input().split() ]
s = (a+b+c)//2
print(int((s*(s-a)*(s-b)*(s-c))**0.5))

Solution (Python):
a,b,c=map(int,input().split())
print(a*b//2)

Solution (Python):
a, b, c = map(int, input().split())
print(a * b // 2)

Solution (Python):
inl=list(map(int,input().split()))
inl.sort()
print(inl[0]*inl[1]//2)

Solution (Python):
a,b,_ = map(int,input().split())
print((a*b)//2)

Solution (Python):

lst_1 = input().split()

for i in range(len(lst_1)):

    lst_1[i] = int(lst_1[i])

lst_1.sort()

ans = int(lst_1[0] * lst_1[1] / 2)

print(ans)

Solution (Python):
ab, bc, ca = map(int, input().split())
area = int(bc*ab/2)
print(area)

Solution (Python):



def solve(AB, BC, CA):
    print(int(AB * BC * 0.5))




def main():
    AB, BC, CA = list(map(int, input().split()))
    solve(AB, BC, CA)
    
    pass


if __name__ == '__main__':
    main()

Solution (Python):
a, b, c = map(int, input().split())
if(a*a + b*b == c*c):
    print(a*b//2)
elif(b*b + c*c == a*a):
    print(b*c//2)
else:
    print(c*a//2)

Solution (Python):
AB, BC, CA = list(map(int,input().split()))
print(int(AB*BC/2))

Solution (Python):


AB, BC, CA = map(int, input().split())

print (int((AB*BC) / 2))

Solution (Python):
p, q, r = map(int, input().split())
print(int(p*q/2))

Solution (Python):
L = list(map(int, input().split()))
L.sort()
print(int(L[0] * L[1] / 2))

Solution (Python):
l = input().split()
A = int(l[0])
B = int(l[1])
C = int(l[2])
ans = (A * B)/2
print(int(ans))

Solution (Python):
a = [int(num) for num in input().split()]

a.sort(reverse=False)

print(int(a[0]*a[1]/2))

Solution (Python):
A , B , C=map(int , input().split())
print(int(A*B/2))

Solution (Python):
AB,BC,CA= input().split()

AB = int(AB)
BC = int(BC)
CA = int(CA)

S = (AB * BC) / 2
print(int(S))

Solution (Python):
a,b,_=map(int, input().split())
print(int(a*b/2))

Solution (Python):
AB, BC, CA = map(int, input().split())
print(int(AB*BC/2))

Solution (Python):
A, B, C = map(int, input().split())

print(A * B // 2)

Solution (Python):
A,B,C = map(int,input().split())
print(A*B//2)

Solution (Python):
ab, bc, ca = map(int, input().split())
print((ab * bc) // 2)

Solution (Python):
l = list(map(int, input().split()))
print(int(l[0]*l[1]/2))

Solution (Python):
a, b, c = map(int, input().split())
print(a * b // 2)

Solution (Python):
a,b,c = map(int,input().split(" "))
print(int((a*b)/2))

Solution (Python):
ab,bc,ca = map(int,input().split())
print(bc*ab//2)

Solution (Python):
A, B, C = map(int,input().split())

ans = A * B / 2
print(int(ans))

Solution (Python):
def main():
    ab, bc, ca = map(int, input().split())

    longest = max(ab, bc, ca)

    if longest == ab:
        print(bc * ca // 2)
    if longest == bc:
        print(ca * ab // 2)
    if longest == ca:
        print(ab * bc // 2)

if __name__ == "__main__":
    main()

Solution (Python):
ab, bc, ca = map(int, input().split())
print(ab * bc // 2)

Solution (Python):
AB, BC, CA = [int(abc) for abc in input().split()]
print(int(AB*BC/2))

Solution (Python):
a, b, c = map(int, input().split())
area = int(1/2*a*b)
print(area)

Solution (Python):
side = [int(x) for x in input().split()]
side.sort()
 
print(int(side[0]*side[1]/2))

Solution (Python):
a,b,c=map(int,input().split())
print(int(a*b/2))

Solution (Python):
AB, BC, _ = map(int, input().split())

print(AB * BC // 2)

Solution (Python):
a,b,c=map(int, input().split())
print(int(a*b/2))

Solution (Python):
a,b,c=map(int,input().split())
print((a*b)//2)

Solution (Python):
a,b,c = map(int, input().split())
print(int(1 / 2 * a * b))

Solution (Python):
ab,bc,ca=map(int,input().split())
print(ab*bc//2)

Solution (Python):





def main():
    L = list(map(int,input().split()))

    s = sum(L)/2

    S = (s*(s-L[0])*(s-L[1])*(s-L[2])) ** 0.5

    print(int(S))


if __name__ == '__main__':
    main()

Solution (Python):
ab, bc, ca = map(int, input().split())
S = int((ab * bc) /2)
print(S)

Solution (Python):
c, a, b = map(int, input().split())
print(c * a // 2)

Solution (Python):
a = list(map(int, input().split()))
a = sorted(a)
print(a[0] * a[1] // 2)

Solution (Python):
a,b,c = map(int,input().split())
print(int(a*b/2))

Solution (Python):
a, b, c= input().split()
a, b, c = int(a), int(b), int(c)

if a>b and a>c:
  print(int((1/2 * b * c)))
  
if b>a and b>c:
  print(int((1/2 * a * c)))
  
else:
  print(int((1/2 * a *b)))

Solution (Python):
inp = list(sorted([int(x) for x in input().split()]))
print((inp[0]*inp[1])//2)

Solution (Python):
a,b,c = map(int,input().split())
print(a*b//2)

Solution (Python):
e = list(map(int, input().split()))
e.sort()
print(int(e[0]*e[1]*(1/2)))

Solution (Python):
a,b,c = map(int, input().split())
print (a * b // 2)

Solution (Python):
tri = list(map(int, input().split()))
print(tri[0] * tri[1] // 2)

Solution (Python):
ab,bc,ca = map(int, input().split())

print(int(ab * bc / 2))

Solution (Python):
ab, bc, ca = map(int, input().split())
print(int(ab * bc / 2))

Solution (Python):
a, b, c = map(int, input().split())
print(a*b//2)

Solution (Python):
x = input()
box= x.split(" ")

add = int(box[0]) * int(box[1])/ 2
print(int(add))

Solution (Python):
a,b,c=map(int,input().split())
print(a*b//2)

Solution (Python):
a, b, c = map(int,input().split())

print(a*b//2)

Solution (Python):
a,b,c = map(int,input().split())
print(int((1/2)*a*b))

Solution (Python):
a,b,c=map(int,input().split())

print(a*b//2)

Solution (Python):
a,b,c=map(int,input().split())
print(a*b*c//max(a,b,c)//2)

Solution (Python):
R= list(map(int,input().split()))
R.sort()
print(R[0] * R[1] // 2)

Solution (Python):
h, w, x = map(int, input().split(' '))
print(int((h * w)/2))

Solution (Python):
import math

l = list(map(int, input().split()))

s = sum(l)/2

ans = int(math.sqrt(s * (s - l[0]) * (s - l[1]) * (s - l[2])))
print(ans)

Solution (Python):
triangle = [int(i) for i in input().split()]

triangle.sort()

area = triangle[0] * triangle[1] / 2

print(int(area))

Solution (Python):
a=list(map(int,input().split()))
a.sort()
print(int(a[0]*a[1]/2))

Solution (Python):
ab,bc,ca=map(int,input().split())
print(int(ab*bc/2))

Solution (Python):

"""
A - Right Triangle
https://atcoder.jp/contests/abc116/tasks/abc116_a

"""
import sys


def solve(a, b, c):
    s = (a + b + c) / 2
    return int((s*(s-a)*(s-b)*(s-c))**0.5)

def main(args):
    a, b, c = map(int, input().split())
    ans = solve(a, b, c)
    print(ans)


if __name__ == '__main__':
    main(sys.argv[1:])

Solution (Python):
from __future__ import print_function
import numpy as np
import sys
import math,string,itertools,fractions,heapq,collections,re,array,bisect,copy,functools


import random

def eprint(*args, **kwargs):
    print(*args, file=sys.stderr, **kwargs)

a,b,c = map(int, input().split())
print(int(a*b/2))

Solution (Python):
i = list(map(int, input().split()))
ab = i[0]
bc = i[1]
ca = i[2]

print(round(ab * bc / 2));

Solution (Python):
import sys


def input():
    return sys.stdin.readline()[:-1]








a,b,c=map(int,input().split())
print(int(a*b/2))

Solution (Python):
A, B, C = [int(i) for i in input().split()]
print(A*B//2)

Solution (Python):
AB,BC,CA = map(int,input().split())
print(int(AB*BC/2))

Solution (Python):
import sys
import bisect
input = sys.stdin.readline

L = [int(v) for v in input().split()]

print(L[0] * L[1] // 2)

Solution (Python):
a, b, c = map(int, input().split(' '))
print(a*b//2)

Solution (Python):
A,B,C = map(int,input().split())
print(A*B//2)

Solution (Python):
abc = list(sorted(map(int, input().split())))
print(int(abc[0]*abc[1]*(1/2)))

Solution (Python):
a,b,c = map(int, input().split())
if a == max(a,b,c):
    print(int(b*c / 2))
elif b == max(a,b,c):
    print(int(a*c / 2))
elif c == max(a,b,c):
    print(int(a*b / 2))

Solution (Python):
a,b,c = map(int,input().split())
print(int(a*b/2))

Solution (Python):
from functools import reduce
from operator import mul
T = [int(x) for x in input().split()]
print(reduce(mul, sorted(T)[0:2]) // 2)

Solution (Python):
d=list(map(int,input().split()))
d.sort()
print(d[0]*d[1]//2)

Solution (Python):
AB, BC, CA = map(int, input().split())

print(int(AB * BC / 2))

Solution (Python):
A,B,C=map(int,input().split())
print(int(A*B/2))

Solution (Python):
a, b, c = map(int, input().split())
print(a*b//2)

Solution (Python):
a,b,c=sorted(map(int, input().split()))
print(a*b//2)

Solution (Python):
c,a,b=map(int,input().split())

S=c*a/2

print(int(S))

Solution (Python):
a,b,c=(int(i) for i in input().split())
 
s=(a+b+c)/2
 
print(int((s*(s-a)*(s-b)*(s-c))**(1/2)))

Solution (Python):
A,B,C = map(int,input().split())
 
print(A*B//2)

Solution (Python):
import math
 
a, b, c = map(int, input().split())
 
s = (a+b+c) / 2
summ = s * (s-a) * (s-b) * (s-c)
print(int(math.sqrt(summ)))

Solution (Python):


a, b, c = map(int, input().split())
M = max(a,b,c)
x = a*b*c//(M*2)
print(x)

Solution (Python):
a, b, c = [int(c) for c in input().split()]

print(a * b // 2)

Solution (Python):
import sys
input = sys.stdin.readline

x = list(map(int, input().split()))
x.sort()

print(int(x[0]*x[1]/2))

Solution (Python):
A, B, C = list(map(int, input().split()))

if A > B and A > C:
    print(str(B*C//2))
elif B > A and B > C:
    print(str(A*C//2))
else:
    print(str(A*B//2))

Solution (Python):
x, y, z = map(int,input().split())
print(x * y // 2)

Solution (Python):
if __name__ == '__main__':
    AB, BC, CA = map(int, input().split())

    answer = int((AB * BC)/2)
    print(answer)

Solution (Python):
l = list(map(int, input().split()))
l.sort()
l.reverse()
l.pop(0)
print(l[0]*l[1]//2)

Solution (Python):
a = list(map(int,input().split()))

a = sorted(a)

print(int(a[0]*a[1]/2))

Solution (Python):
ab, bc, _ = map(int, input().split())
print(int(ab*bc/2))

Solution (Python):
ab, bc, ca = map(int, input().split())

print(int(ab*bc/2))

Solution (Python):
i=list(map(int, input().split())) 
i.sort()
print(int(i[0]*i[1]*0.5))

Solution (Python):
A, B, C= list(map(int, input().split()))

print (A * B //2)

Solution (Python):
A,B,C=map(int,input().split())
print(int(A*B/2))

Solution (Python):
a, b, c = map(int, input().split())
print(int(a * b / 2))

Solution (Python):
ab, bc, ca = map(int, input().split())

S = int(ab * bc / 2)
print(S)

Solution (Python):
ab, bc, ca = map(int, input().split())

S = int(ab * bc / 2)
print(S)

Solution (Python):
nums = sorted(map(int, input().split()))
print(round(nums[0]*nums[1]/2))

Solution (Python):
x,y,z = map(int,input().split())
print(int(x * y / 2))

Solution (Python):
AB, BC, CA = map(int, input().split())
print(AB * BC // 2)

Solution (Python):
a,b,c=map(int,input().split())
print(a*b//2)

Solution (Python):
A,B,C = map(int,input().split())
print(int(A*B/2))

Solution (Python):
a,b,c=map(int,input().split())
print(int(a*b/2))

Solution (Python):
[a,b,c] = [int(j) for j in input().split()]
x = [a,b,c]
d = min(x)
e = a+b+c-d-max(x)
print(int(d*e/2))

Solution (Python):
AB, BC, CA = map(int, input().split())

print(AB * BC // 2)

Solution (Python):
a,b,c=map(int,input().split())
print(a*b*c//max(a,b,c)//2)

Solution (Python):
a, b, c = map(int,input().split())
print(int(a*b/2))

Solution (Python):
x, y, z = map(int, input().split())

print(int(x*y/2))

Solution (Python):
arr = list(map(int, input().split()))
print(arr[1] * arr[0] // 2)

Solution (Python):
a,b,c = map(int,input().split())

print(int(a*b/2))

Solution (Python):
AB,BC,CA = map(int,input().split())

print(round(AB*BC/2))

Solution (Python):
A,B,C=[int(a) for a in input().split(" ")]
print(A*B//2)

Solution (Python):
a,b,c = map(int, input().split())
print(int(a*b/2))

Solution (Python):
c, a, b = map(int,input().split())
print(a*c//2)

Solution (Python):
a, b, c = map(int, input().split())

print(int(b * a / 2))

Solution (Python):
a,b,c = map(int,(input().split()))
print(a*b//2)

Solution (Python):
ab, bc, ca = map(int, input().split())

print(int(ab*bc/2))

Solution (Python):
a, b, c = map(int, input().split())

print(int((a*b)/2))

Solution (Python):
a, b, c = map(int, input().split())
print(int(a*b/2))

Solution (Python):
import math
a, b, c = map(int, input().split())
s = (a+b+c)/2
print(int(math.sqrt((s*(s-a)*(s-b)*(s-c)))))

Solution (Python):


def solve():
    ab, bc, ca = list(map(int, input().split()))
    print(int(ab*bc/2))

if __name__ == "__main__":
    solve()

Solution (Python):
a, b, c = map(int,input().split())
print(int((a*b)/2))

Solution (Python):
AB,BC,CA = map(int,input().split())
print(int(AB*BC/2))

Solution (Python):
AB,BC,AC = list(map(int,input().split()))
print(int(AB * BC / 2))

Solution (Python):
a = list(map(int, input().split()))
a.remove(max(a))
print(int(a[0]*a[1]*0.5))

Solution (Python):
l1, l2, l3 = map(int,input().split())
print(int(l1 * l2 / 2))

Solution (Python):
AB, BC, CA = map(int, input().split())
print(AB * BC //2)

Solution (Python):
A, B, C = map(int, input().split())

print (A * B //2)

Solution (Python):
c,a,b = map(int, input().split())
print(int(a * c / 2))

Solution (Python):
c,a,b  = [int(i) for i in input().split()]
print(int(a*c/2))

Solution (Python):
AB, BC, CA = map(int, input().split())

print(AB * BC // 2)

Solution (Python):
a, b, c = list(map(int, input().split()))
print(a*b//2)

Solution (Python):
AB,BC,CA = map(int,input().split())

print(int(AB*BC/2))