Problem:
 Score : 400 points    Problem Statement Given are integers A , B , and N .  Find the maximum possible value of floor(Ax/B) - A × floor(x/B) for a non-negative integer x not greater than N .  Here floor(t) denotes the greatest integer not greater than the real number t .      Constraints  1 ≤ A ≤ 10^{6}  1 ≤ B ≤ 10^{12}  1 ≤ N ≤ 10^{12}  All values in input are integers.         Input Input is given from Standard Input in the following format:  A  B  N       Output Print the maximum possible value of floor(Ax/B) - A × floor(x/B) for a non-negative integer x not greater than N , as an integer.        Sample Input 1 5 7 4      Sample Output 1 2  When x=3 , floor(Ax/B)-A×floor(x/B) = floor(15/7) - 5×floor(3/7) = 2 . This is the maximum value possible.       Sample Input 2 11 10 9      Sample Output 2 9

Solution (Python):
a, b, n = map(int, input().split())
ans = 0
if n < b-1:
    ans = int(a*(n)/b)
else:
    ans = int(a*(b-1)/b)
print(ans)

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

if n>=b:
    print((a*(b-1))//b)
else:
    print((a*n)//b)

Solution (Python):
import math
def main():
    A, B, N = map(int, input().split())
    ans = 0
    if N < B:
        ans = math.floor((A*N)/B) - A*math.floor(N/B)
    else:
        ans = math.floor((A*(B-1)/B)) - A*math.floor((B-1)/B)
    print(ans)

if __name__ == "__main__":
    main()

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

A, B, N = map(int, readline().split())

beta = B-1 if N >= B else N
print(A*beta//B)

Solution (Python):

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





i=min(b-1,n)
print(int((a*i/b)//1-a*((i/b)//1)))

Solution (Python):
import math
a,b,n = map(int,input().split())
if b>n:
    x = n
else:
    x = b-1
print(math.floor(a*x/b))

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

temp = min(n,b-1)
ans= int(a/b*temp)
print(ans)

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

i = min(b-1,n)
print(int((a*i)/b)-a*int(i/b))

Solution (Python):
a , b , n = map(int , input().split())
l = 0
r = n
ans = 0
while (l < r) :
    mid = (l + r + 1) // 2
    if  (a * mid) // b - a * (mid // b) >= ans :
         ans =  (a * mid) // b - a * (mid // b)
         l = mid
    else :
        r = mid - 1
print((a * r) // b - a * (r // b))

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

l = None
if B <= N:
    l = B-1
else:
    l = N



'''
for x in range(1, len(l) + 1):
    l[x-1] = ((A*x)//B) - A*(x//B)
'''

print(((A*l)//B) - A*(l//B))



'''m = 0
for x in range(1, N+1):
    j =  ((A*x)//B) - A*(x//B)
    m = max(m,j)


print('MAX',m)
'''

Solution (Python):
import math


A,B,N = map(int, input().split())

def func(x):
    return math.floor(A*x / B) - A * math.floor(x / B)
"""
for i in range(N+1):
    print(i, func(i))
"""


if N >= B:

    print(func(B-1))
else:
    print(func(N))

Solution (Python):


A, B, N = map(int, input().split())

X = min(B-1, N)

print((A*X)//B - A*(X//B))

Solution (Python):
a,b,n = [int(x) for x in input().split()]
import math,bisect
if b>n:
    i = n
    x = math.floor(a*i/b)-math.floor(i/b)*a
    print(x)
else:
    x = math.floor(a*(b-1)/b)
    print(x)

Solution (Python):
a, b, n = map(int, input().split())
if b-1 <= n:
    x = b-1
else:
    x = n
max_num = int(a * x / b) - a * int(x / b)
print(max_num)

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

if N / B >= 1:
    r = B - 1
else:
    r = N

print(int(A*r/B))

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

def f(a, b, x):
	return (a * x) // b - a * (x // b)

print(f(a, b, min(b-1, n)))

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

x = B-1
if B > N:
    x = N
ans = int(A*x/B) - A*int(x/B)
print(ans)

Solution (Python):
a,b,n= list(map(int, input().split()))
if b==1:
    print(0)
    exit(0)
ma=(a*n/b)//1-a*((n/b)//1)
for i in range(b-1,n+1,b):
    tmp=(a*i/b)//1-a*((i/b)//1)
    ma=max(tmp,ma)
print(int(ma))

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


def fl(n):
    global a, b
    return (a * n) // b


def fr(n):
    global a, b
    return a * (n // b)


def f(n):
    return fl(n)-fr(n)


target = n - ((n+1) % b)

print(f(target) if target > 0 else f(n))

Solution (Python):
def floor(t):
    return int(t)

a,b,n = map(int,input().split())
if n<b:
    ans = floor((a*n)/b) - a*floor(n/b)
else:
    ans = floor((a*(b-1))/b) - a*floor((b-1)/b)
print(ans)

Solution (Python):
a,b,n=map(int, input().split())
if n < b:
    print((a*n)//b - a*(n//b))
else:
    print((a*(b-1))//b - a*((b-1)//b))

Solution (Python):
import sys
from itertools import combinations_with_replacement
def input(): return sys.stdin.readline().strip()


def main():
    A, B, N = map(int, input().split())
    if N >= B:
        r = (B - 1) / B
    else:
        r = min(N, (B - 1)) / B
    print(int(A * r))



    


if __name__ == "__main__":
    main()

Solution (Python):
import numpy as np

A,B,N=list(map(int,input().split()))

x=min(B-1,N)

print(int(np.floor(A*(x%B)/B)))

Solution (Python):
a,b,n=map(int,input().split())
ans=0

def f(x):
    return (a*x)//b - a*(x//b)

if b>=n:
    ans=max(f(n),f(n-1))
elif a<b:
    ans = f(b-1)
print(ans)

Solution (Python):
import numpy as np
import math
import pprint

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

if(b<=n):
  print(int(a*(b-1)/b))
else:
  print(int(a*n/b))

Solution (Python):
A, B, N = map(int, input().split())
if N >= B:
    ans = (A*(B-1))//B
else:
    ans = (A*N)//B

print(ans)

Solution (Python):
import itertools
from collections import deque,defaultdict,Counter
from itertools import accumulate
import bisect
from heapq import heappop,heappush,heapify
import math
from copy import deepcopy
import queue

Mod = 1000000007
  
def sieve_of_eratosthenes(n):
    if not isinstance(n,int):
        raise TypeError("n is not int")
    if n<2:
        raise ValueError("n is not effective")
    prime = [1]*(n+1)
    for i in range(2,int(math.sqrt(n))+1):
        if prime[i] == 1:
            for j in range(2*i,n+1):
                if j%i == 0:
                    prime[j] = 0
    res = []
    for i in range(2,n+1):
        if prime[i] == 1:
            res.append(i)
    return res

 
class UnionFind:
    def __init__(self,n):
        self.parent = [i for i in range(n+1)]
        self.rank = [0 for i in range(n+1)]
    
    def findroot(self,x):
        if x == self.parent[x]:
            return x
        else:
            y = self.parent[x]
            y = self.findroot(self.parent[x])
            return y
    
    def union(self,x,y):
        px = self.findroot(x)
        py = self.findroot(y)
        if px < py:
            self.parent[py] = px
        else:
            self.parent[px] = py
 
    def same_group_or_no(self,x,y):
        return self.findroot(x) == self.findroot(y)

def main():  
    a, b, n = map(int, input().split())
    if b == 1:
        print(0)
    elif b > n:
        print(a * n // b - a * (n  // b))
    else:
        x = (b - 1) * (n // (b - 1))
        print(a*x // b - a*(x//b))
if __name__ == "__main__":
    main()

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

if B - 1 > N:
    print((A * N) // B - A * (N // B))
    exit()

print(A - (A + B - 1) // B)

Solution (Python):
import sys
import math
from collections import deque
import heapq
MAX_INT = int(10e10)
MIN_INT = -MAX_INT
mod = 1000000007
sys.setrecursionlimit(1000000)
def IL(): return list(map(int,input().split()))
def SL(): return input().split()
def I(): return int(sys.stdin.readline())
def S(): return input()

def tami(a,b,i):
  num = (a*i)//b - a*(i//b)
  return num

a,b,N = IL()

l = [0,b-1,N,(N//b)*b-1]
ans = 0
for i in l:
  if 0 <= i <= N:
    ans = max(ans, tami(a,b,i))
print(ans)

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


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




if c >= b:
    print((a * (b-1)) // b)

else:
    x = c
    c_amari = c%b
    c_sho = c//b
    ans =(a * c_amari) //b
    print(ans)

Solution (Python):
import math
A,B,N = map(int,input().split())
looked = min(B-1,N)
ans = (A*looked)//B - A*(looked//B)
print(ans)

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

ans=(min(b-1,n)*a)//b
print(ans)

Solution (Python):
from math import floor
a, b, n = map(int, input().split())
if n >= b:
    x = b-1
else:
    x = n
ansx = floor(a*x/b) - a*floor(x/b)
print(ansx)

Solution (Python):


import math

def main():
     a, b, n = map(int, input().split())
     
     

     
     
     
     
     
     
     
     

     
     
     

     if n < b:
          ans = math.floor((a * n / b)) - a * math.floor(n / b)
     else:
          ans = math.floor((a * (b - 1) / b)) - a * math.floor((b - 1) / b)

     print(ans)

if __name__ == "__main__":
    main()

Solution (Python):
a, b, n = map(int, input().split())
if b == 1:
  print(0)
else:
  if n >= b-1:
    print(a-1-a//b)
  else:
    print((a*n)//b - a*(n//b))

Solution (Python):
a,b,n = map(int,input().split())
p = (n+1)//b
c = p*b-1
if c < 0:
  print(a*n//b-a*(n//b))
  exit()
ans = max(a*n//b-a*(n//b),a*c//b-a*(c//b))
print(ans)

Solution (Python):
def resolve():
    import math
    a, b, n = map(int, input().split())
    if b<= n:
        x = b-1
    else:
        x = n
    print(math.floor(a*x/b) - a*math.floor(x/b))
resolve()

Solution (Python):
def main():
    ans = 0
    a,b,n = map(int, input().split())
    if b > n:
        ans = (a*n)//b - a*(n//b)
    else:
        ans = (a*(b-1))//b - a*((b-1)//b)
    print(ans)

if __name__ == '__main__':
    main()

Solution (Python):
a,b,n=map(int,input().split())
r=min(n,b-1)
print((a*r)//b)

Solution (Python):
import math
import sys

stdin = sys.stdin

ns = lambda: stdin.readline().rstrip()
ni = lambda: int(stdin.readline().rstrip())
nm = lambda: map(int, stdin.readline().split())
nl = lambda: list(map(int, stdin.readline().split()))
mod = 10**9 + 7 
sys.setrecursionlimit(1000010)

A,B,N = nm()
q = min(B-1,N)
print(A*q // B)

Solution (Python):
from heapq import *
import sys
from collections import *
from itertools import *
from decimal import *
import copy
from bisect import *
import math
sys.setrecursionlimit(4100000)
def gcd(a,b):
    if(a%b==0):return(b)
    return (gcd(b,a%b))
input=lambda :sys.stdin.readline().rstrip()

A,B,N=map(int,input().split())
def main2(x):
    
    return(int(A*x/B)-A*int(x/B))
def main(x):
    
    return(A*x//B-A*(x//B))

if N>=B-1:
    Z=B-1
else:
    Z=N
print((main2(Z)))

Solution (Python):



import math
import itertools
from collections import defaultdict
from collections import Counter
import numpy as np

import heapq
a,b,n=list(map(int,input().split()))
if n<b:
    print(math.floor(a*n/b))
    exit()

print(math.floor(a*(b-1)/b))

Solution (Python):
def main(sample_file = ''):

    """ convenient functions
    
    
    
    
    
    """

    """convenient decorator
    
    
        
        
        
        
        
        
        
        
        
        
    """
    
    
    import sys
    sys.setrecursionlimit(10**7)
    from itertools import accumulate, combinations, permutations, product 
    
    from math import factorial, ceil, floor, sqrt
    def factorize(n):
        """return the factors of the Arg and count of each factor
        
        Args:
            n (long): number to be resolved into factors
        
        Returns:
            list of tuples: factorize(220) returns [(2, 2), (5, 1), (11, 1)]
        """
        fct = []  
        b, e = 2, 0  
        while b * b <= n:
            while n % b == 0:
                n = n // b
                e = e + 1
            if e > 0:
                fct.append((b, e))
            b, e = b + 1, 0
        if n > 1:
            fct.append((n, 1))
        return fct
    def combinations_count(n, r):   
        """Return the number of selecting r pieces of items from n kinds of items.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        
        if n < 0 or r < 0:
            raise Exception('combinations_count(n, r) not defined when n or r is negative')
        if n - r < r: r = n - r
        if r < 0: return 0
        if r == 0: return 1
        if r == 1: return n
        numerator = [n - r + k + 1 for k in range(r)]
        denominator = [k + 1 for k in range(r)]
        for p in range(2,r+1):
            pivot = denominator[p - 1]
            if pivot > 1:
                offset = (n - r) % p
                for k in range(p-1,r,p):
                    numerator[k - offset] /= pivot
                    denominator[k] /= pivot
        result = 1
        for k in range(r):
            if numerator[k] > 1:
                result *= int(numerator[k])
        return result
    def combinations_with_replacement_count(n, r):
        """Return the number of selecting r pieces of items from n kinds of items allowing individual elements to be repeated more than once.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        if n < 0 or r < 0:
            raise Exception('combinations_with_replacement_count(n, r) not defined when n or r is negative')
        elif n == 0:
            return 1
        else:
            return combinations_count(n + r - 1, r)
    from bisect import bisect_left, bisect_right
    from collections import deque, Counter, defaultdict 
    from heapq import heapify, heappop, heappush, heappushpop, heapreplace,nlargest,nsmallest 
    from copy import deepcopy, copy 
    import operator
    from operator import itemgetter 
    
    
    from functools import reduce, lru_cache
    def chmin(x, y):
        """change minimum
        if x > y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current minimum value
            y (long): potential minimum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x > y:
            x = y
            return (x, True)
        else:
            return (x, False)
    def chmax(x, y):
        """change maximum
        if x < y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current maximum value
            y (long): potential maximum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x < y:
            x = y
            return (x, True)
        else:
            return (x, False)

    from fractions import gcd 
    def gcds(numbers):
        return reduce(gcd, numbers)
    def lcm(x, y):
        return (x * y) // gcd(x, y)
    def lcms(numbers):
        return reduce(lcm, numbers, 1)
    def make_divisors(n, reversed=False):
        """create list of divisors
        
        Args:
            number (int): number from which list of divisors is created
            reversed (bool, optional): ascending order if False. Defaults to False.
        
        Returns:
            list: list of divisors
        """
        divisors = set()
        for i in range(1, int(n**0.5)+1):
            if n % i == 0:
                divisors.add(i)
                divisors.add(n//i)
        return sorted(list(divisors),reverse=reversed)
    
    
    
    INF = 10 ** 18
    MOD = 10 ** 9 + 7
    AtoZ = list('abcdefghijklmnopqrsruvwxyz')
    modpow = lambda a, n, p = MOD: pow(a, n, p) 
    def modinv(a, p = MOD):
        
        
        return modpow(a, p-2, p)
    def modinv_list(n, p = MOD):
        if n <= 1:
            return [0,1][:n+1]
        else:
            inv_t = [0,1]
            for i in range(2, n+1):
                inv_t += [inv_t[p % i] * (p - int(p / i)) % p]
            return inv_t
    def modfactorial_list(n, p = MOD):
        if n == 0:
            return [1]
        else:
            l = [0] * (n+1)
            tmp = 1
            for i in range(1, n+1):
                tmp = tmp * i % p
                l[i] = tmp
            return l
    def modcomb(n, k, fac_list = [], p = MOD):
        
        
        from math import factorial
        if n < 0 or k < 0 or n < k: return 0
        if n == 0 or k == 0: return 1
        if len(fac_list) <= n:
            a = factorial(n) % p
            b = factorial(k) % p
            c = factorial(n-k) % p
        else:
            a = fac_list[n]
            b = fac_list[k]
            c = fac_list[n-k]
        return (a * modpow(b, p-2, p) * modpow(c, p-2, p)) % p
    def modadd(a, b, p = MOD):
        return (a + b) % MOD
    def modsub(a, b, p = MOD):
        return (a - b) % p
    def modmul(a, b, p = MOD):
        return ((a % p) * (b % p)) % p
    def moddiv(a, b, p = MOD):
        return modmul(a, modpow(b, p-2, p))

    class UnionFindTree:
        """union find tree class
        TODO: fix this description...
        how to use (example):
        >>  uf = UnionFindTree(N) 
        >>  if uf.find_root(a) == uf.find_root(b):
        >>      do something
        >>  else:
        >>      do something
        >>      uf.unite(a, b)
        """
        def __init__(self, N):
            self.root = [-1] * (N+1)
            self.rank   = [0]  * (N+1)
            self.connected_num = [1] * (N+1)
    
        def find_root(self,x):
            root = self.root
            while root[x] != -1:
                x = root[x]
            return x
    
        def unite(self,x,y):
            root = self.root
            rank = self.rank
            connected_num = self.connected_num
            find_root = self.find_root
    
            rx = find_root(x)
            ry = find_root(y)
            if rx != ry:
                if rank[rx] < rank[ry]:
                    root[rx] = ry
                    rx,ry = ry,rx
                else:
                    if rank[rx] == rank[ry]:
                        rank[rx] += 1
                    root[ry] = rx       
                connected_num[rx] += connected_num[ry]

    
    
    
    
    

    def BellmanFord(N, M, ABC, vertex_start, vertex_end, value_if_inf = -1, find_shortest = False):
        """to calculate furthest or shortest length between vertex_start and vertex_end using BellmanFord algorithm
        
        Args:
            N (int): number of vertices
            M (int): number of edges
            ABC (list): [(ai, bi, ci) for _ in range(N)] where i-th edge is directed from vertex ai to vertex bi and the length is ci 
            vertex_start (int): start vertex. usually use 0.
            vertex_end (int): end vertex. usually use N-1.
            value_if_inf (int or string as you like, optional): value you want when the furthest (or shortest) distance is infinite (or -infinite). Defaults to -1.
            find_shortest (bool, optional): choose False to find furthest path. Defaults to False.
        
        Returns:
            int or string: normally int (but can be str if you set value_if_inf to str)
            
        Example:
                N, M, P = R()
                ABC = [R() for _ in range(M)]
                ABC = [(a-1, b-1, c-P) for a, b, c in ABC]
                print(BellmanFord(N, M, ABC, 0, N-1, value_if_inf = 'inf'))

        """

        def make_reachable_list(N, M, ABC, vertex_start, vertex_end):
            reachable_to_direct = defaultdict(list)
            reachable_from_direct = defaultdict(list)
            reachable_from_start = [False] * N
            reachable_to_end = [False] * N
            reachable_from_start[vertex_start] = True
            reachable_to_end[vertex_end] = True
            reachable_from_both_sides = [False] * N
            dfs_from_start = []
            dfs_to_end = []
            for a, b, c in ABC:
                reachable_to_direct[a].append(b)
                reachable_from_direct[b].append(a)
                if a == vertex_start:
                    dfs_from_start.append(b)
                    reachable_from_start[b] = True
                if b == vertex_end:
                    dfs_to_end.append(a)
                    reachable_to_end[a] = True
            while dfs_from_start:
                v = dfs_from_start.pop()
                for i in reachable_to_direct[v]:
                    if not reachable_from_start[i]:
                        reachable_from_start[i] = True
                        dfs_from_start.append(i)
            while dfs_to_end:
                v = dfs_to_end.pop()
                for i in reachable_from_direct[v]:
                    if not reachable_to_end[i]:
                        reachable_to_end[i] = True
                        dfs_to_end.append(i)
            for i in range(N):
                reachable_from_both_sides[i] = reachable_from_start[i] and reachable_to_end[i]
            return reachable_from_both_sides
        
        reachable_from_both_sides = make_reachable_list(N, M, ABC, vertex_start, vertex_end)
        
        if find_shortest:
            dist = [INF for i in range(N)]
        else:
            dist = [-INF for i in range(N)]
        
        dist[vertex_start] = 0
        for i in range(N):
            updated = False
            for a, b, c in ABC:
                if not reachable_from_both_sides[a]:
                    continue
                elif find_shortest:
                    update_condition = dist[a] + c < dist[b]
                else:
                    update_condition = dist[a] + c > dist[b]
                if dist[a] != INF and update_condition:
                    dist[b] = dist[a] + c
                    updated = True
                    if i == N-1:
                        return value_if_inf
            if not updated:
                break
        return dist[vertex_end]

    """ initialize variables and set inputs
    
        
        
            
            
    
        
        
        
        
        
        
        
    
        
        
        
        
    
        
        
    """

    
    r = lambda: sys.stdin.readline().strip()
    r_int = lambda: int(r())
    r_float = lambda: float(r())
    R = lambda: list(map(int, r().split()))
    R_str = lambda: r().split()
    R_map = lambda: map(int, r().split())
    R_float = lambda: list(map(float, r().split()))
    R_tuple = lambda: tuple(map(int, r().split()))

    """ how to treat input
    
    
    
    
    
    
    
    """

    
    if sample_file:
        sys.stdin = open(sample_file)
        
    
    
    
    A, B, N = R()
    if N >= B:
        print(floor(A*(B-1)/B) - A * floor((B-1)/B))
    else:
        print(floor(A*(N)/B) - A * floor((N)/B))
    
    
    

    """memo: how to use defaultdict of list
    
    Dic = defaultdict(list)
    
    Dic[x].append(y)
    
    for k, v in Dic.items():
    """
    
    """memo: how to solve binary problems
    
    >>> a = 5
    >>> bin_str_a = format(a, '
    >>> print(bin_str_a)
    0b0101 
    """
    
    """memo: how to solve the problem
    creating simple test/answer
    greed
    simple dp
    graph
    """

if __name__ == '__main__':
    main()

Solution (Python):
a, b, n = map(int, input().split())
if n < b:
    print(a * n // b)
else:
    print(a * (b-1) // b)

Solution (Python):
import math
a, b, n = map(int, input().split())
if b - 1 <= n:
    print(math.floor(a/b*(b-1)) - a * math.floor((b-1)/b))
else:
    print(math.floor(a/b*n) - a * math.floor(n/b))

Solution (Python):
from sys import stdin
a,b,n = [int(x) for x in stdin.readline().rstrip().split()]
if n >= b-1:
    x = b-1
else:
    x = n
ans =int(a*x/b)-a*int(x/b)
print(ans)

Solution (Python):


a, b, n = map(int, input().split())
max_score = 0
if n < b:
    max_score = int(a * n / b) - a * (n // b)
elif n == b:
    max_score = max(int(a * n / b) - a * (n // b), int(a * (n-1) / b) - a * ((n-1) // b))
elif a <= b:
    max_score = a - 1
elif a >= b:
    max_score = int(a * (b-1) / b) - a * ((b-1) // b)
else:
    for x in range(1, n + 1):
        score = int(a * x / b) - a * (x // b)
        if max_score < score:
            max_score = score
print(max_score)

Solution (Python):
abn = [int(i) for i in input().split()]
a = abn[0]
b = abn[1]
n = abn[2]
x = min(b-1, n)
print(int((a*x)/b)-a*int(x/b))

Solution (Python):
import math
A, B, N = map(int, input().split())

def fnc(x):
    return math.floor(A*x*1.0/B) - A*math.floor(x*1.0/B)

if B == 1:
    print(0)
elif N < B:
    print(fnc(N))
else:
    ans = 0
    for i in range(B-1, N+1, B):
        s = fnc(i)
        if s > ans:
            ans = s
    print(ans)

Solution (Python):
import sys


a,b,n = (int(i) for i in input().split())


if n < b-1:
    ans = (a*n//b)

else:
    ans = ((b-1)*a)//b



print(ans)

Solution (Python):
import math
A,B,N = map(int,input().split())

if(N <= B-1):
  ans = math.floor(A*N/B)-A*math.floor(N/B)
else:
  ans = math.floor(A*(B-1)/B)-A*math.floor((B-1)/B)

print(ans)

Solution (Python):
A,B,N=map(int,input().split())
if B!=1:
	p=(N+1)//B
	result=0
	if p!=0:
		for a in range(1,p+1):
			x=a*B-1
			s=(A*x)//B - A*(a-1)
			if result < s:
				result=s
	else:
		result=A*N//B -A*(N//B)
	print(result)
else:
	print(0)

Solution (Python):
import math

A,B,N = map(int, input().split())

if B <= N:
    print(math.floor( (A*(B-1))/B ))
else:
    print(math.floor( (A*N)/B ))

Solution (Python):
def calc(x):
    return A*x//B - A*(x//B)

A, B, N = map(int, input().split())
q = N//B
val = q*B
if val == 0:
    ans = calc(N)
else:
    ans = max(calc(val-1), calc(N))
print(ans)

Solution (Python):
def solve(a, b, n):
    return a * min(b - 1, n) / b

assert solve(5, 7, 4) == 2
assert solve(1, 1, 1) == 0
assert solve(11, 10, 9) == 9

(a, b, n) = map(int, raw_input().split())

print solve(a, b, n)

Solution (Python):
from math import floor
A,B,N = map(int, input().split())
m = A//B
a = A%B
x = min(N,B-1)
print(m*x+floor(a*x/B))

Solution (Python):

A,B,N = map(int, input().split())

if B>N:
    a = (A*N)//B
    b = N//B
    print(a-A*b)
    exit()
else:
    N = B-1
    a = (A*N)//B
    b = N//B
    print(a-A*b)

Solution (Python):
A, B, N = map(int, input().split())
i = (N // B) * B
  
i = i - 1
if i < 0:
  ans = (A * N) // B - A * (N // B)
else:
  ans = (A * i) // B - A * (i // B)
  
print(ans)

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

if b-1<=n:
  x=b-1
else:
  x=n
  
print(str((a*x)//b-a*(x//b)))

Solution (Python):
a,b,n = map(int,input().split())
def floor(x):
    return (a*x)//b - a*(x//b)
ans = 0
if b <= n: 
    '''
    for i in range(b-1,n+1):
        ans = max(ans,floor(i))
        
    print(ans)
    '''
    print(floor(b-1))
else:
    print(floor(n))

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

if N >= B-1:
    print(A * (B-1) // B)
else:
    ans = A * N // B - A * (N//B)
    print(ans)

Solution (Python):


import sys
input = sys.stdin.readline
import math
a,b,N = map(int,input().split())
ans = 0
if b <= N :
    ans = math.floor(a*(b-1)/b)-a*math.floor((b-1)/b)
elif b > N:
    ans = math.floor(a*N/b)-a*math.floor(N/b)


print(ans)

Solution (Python):
import sys,collections as cl,bisect as bs
sys.setrecursionlimit(100000)
input = sys.stdin.readline
mod = 10**9+7
Max = sys.maxsize
def l(): 
    return list(map(int,input().split()))
def m(): 
    return map(int,input().split())
def onem(): 
    return int(input())
def s(x): 
    a = []
    if len(x) == 0:
        return []
    aa = x[0]
    su = 1
    for i in range(len(x)-1):
        if aa != x[i+1]:
            a.append([aa,su])
            aa = x[i+1]
            su = 1
        else:
            su += 1
    a.append([aa,su])
    return a
def jo(x): 
    return " ".join(map(str,x))
def max2(x): 
    return max(map(max,x))
def In(x,a): 
    k = bs.bisect_left(a,x)
    if k != len(a) and a[k] ==  x:
        return True
    else:
        return False

def pow_k(x, n):
    ans = 1
    while n:
        if n % 2:
            ans *= x
        x *= x
        n >>= 1
    return ans

"""
def nibu(x,n,r):
    ll = 0
    rr = r
    while True:
        mid = (ll+rr)//2

    if rr == mid:
        return ll
    if (ここに評価入れる):
        rr = mid
    else:
        ll = mid+import sys,collections as cl,bisect as bs
sys.setrecursionlimit(100000)
input = sys.stdin.readline
mod = 10**9+7
Max = sys.maxsize
def l(): 
    return list(map(int,input().split()))
def m(): 
    return map(int,input().split())
def onem(): 
    return int(input())
def s(x): 
    a = []
    if len(x) == 0:
        return []
    aa = x[0]
    su = 1
    for i in range(len(x)-1):
        if aa != x[i+1]:
            a.append([aa,su])
            aa = x[i+1]
            su = 1
        else:
            su += 1
    a.append([aa,su])
    return a
def jo(x): 
    return " ".join(map(str,x))
def max2(x): 
    return max(map(max,x))
def In(x,a): 
    k = bs.bisect_left(a,x)
    if k != len(a) and a[k] ==  x:
        return True
    else:
        return False

def pow_k(x, n):
    ans = 1
    while n:
        if n % 2:
            ans *= x
        x *= x
        n >>= 1
    return ans

"""
def nibu(x,n,r):
    ll = 0
    rr = r
    while True:
        mid = (ll+rr)//2

    if rr == mid:
        return ll
    if (ここに評価入れる):
        rr = mid
    else:
        ll = mid+1
"""


a,b,n = m()

if a > b:
    print((a*n)//b - a*(n//b))
else:
    po = min(b-1,n)
    print((a*po)//b - a*(po//b))

"""


a,b,n = m()


po = min(b-1,n)
print((a*po)//b - a*(po//b))

Solution (Python):
MOD = 10 ** 9 + 7
INF = 10 ** 11
import sys
sys.setrecursionlimit(100000000)

def main():
    a,b,n = map(int,input().split())
    x = -INF
    if b - 1 <= n:
        x = a*(b - 1)//b - a*((b - 1)//b)
    y = a*n//b - a*(n//b)
    print(max(x,y))
if __name__ == '__main__':
    main()

Solution (Python):
import math
a,b,n = list(map(int,input().split()))
x = 1
temp = 0
res = 0

if (b - 1) > n:
    x = n
    
    
    
    
    
    
else:
    x = (b - 1)

res = math.floor((a*x)/b) - a * math.floor(x/b)
print(res)

Solution (Python):
A,B,N=map(int,input().split())
if B==1:
    print(0)
    exit()

if N==1:
    ans=(A//B)-A*(1//B)
    print(ans)
    exit()
if A==1:
    print(0)
    exit()

if B<N:
    val=B-1
    ans=(A*val)//B-A*(val//B)
elif N<B:
    val=N
    
    ans=(A*val)//B-A*(val//B)
else:
    val=B-1
    ans=(A*val)//B-A*(val//B)

print(ans)

Solution (Python):
A,B,N=map(int,input().split())
if B<=N:
  print(int(A*(B-1)/B))
else:
  print(int(A*N/B))

Solution (Python):
A, B, N = map(int, input().split())
from fractions import gcd

ans = 0

x = min(B-1, N)
p = int((A*x)/B) - A*int(x/B)

ans = p

print(ans)

Solution (Python):
import math

A, B, N = map(int, input().split())

if B - 1 <= N:
    x = B - 1
else:
    x = N

ans = math.floor(A * x / B) - A * math.floor(x / B)
print(ans)

Solution (Python):
import numpy as np
import math
import scipy as sp
import queue
import collections

MOD = 10 ** 9 + 7
INF = 10 ** 9

def main(kwargs):
    a = kwargs["a"]
    b = kwargs["b"]
    n = kwargs["n"]

    for i in range(min(b, n), -1, -1):
        res = a * i // b - a * (i // b)

        if res > 0:
            break

    return res

if __name__ == "__main__":
    kwargs = {}

    cin = input().split()
    
    
    
    kwargs["a"], kwargs["b"], kwargs["n"] = [int(i) for i in cin]

    cout = main(kwargs)
    print(cout)

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

x = (n//b)*b - 1

if x == -1:
    x = n

print((a*x)//b - a*(x//b))

Solution (Python):
import math
a, b, n = map(int, input().split())
x = min(n, b-1)
print((a * x) // b)

Solution (Python):
import math
A,B,N = map(int,input().split())

if B > N:
    x = N
else:
    x = B - 1
print(int(math.floor(A*x/B)-A*math.floor(x/B)))

Solution (Python):
x = input().split(' ')
a = int(x[0])
b = int(x[1])
n = int(x[2])

if n >= b:
  print(int(a*(b-1)/b))
elif n == b:
  print(int(a*(b-1)/b))
else:
  print(int(a*n/b))