Buggy python submission (verdict: Runtime Error):
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [1,2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)
#t.sort()


u = [0 for i in range(len(t))]

#print(a)        
#print(t)
sum = 0
for i in range (len(a)-1,-1,-1):
    k = bisect_left(a,t[i])
    #print(t[i],k)
    if a[k] == t[i] and k < i:
        #print(a[i],t[i],i)
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
        u[k] += 1
print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [1,2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)
#t.sort()


u = [0 for i in range(len(t))]

#print(a)        
#print(t)
sum = 0
for i in range (len(a)-1,-1,-1):
    k = bisect_left(a,t[i])
    print(t[i],k)
    if a[k] == t[i] and k < i:
        #print(a[i],t[i],i)
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
        u[k] += 1
#print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)
t.sort(reverse=True)


u = [0 for i in range(len(t))]

#print(a)        
#print(t)
sum = 0
for i in range (len(a)-1,-1,-1):
    k = bisect_left(a,t[i])
    #print(t[i],k)a
    if a[k] == t[i] and k < i:
        #print(a[i],t[i],i)
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
        u[k] += 1
print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)
t.sort(reverse=True)


u = [0 for i in range(len(t))]

#print(a)        
#print(t)
sum = 0
for i in range (len(a)-1,-1,-1):
    k = bisect_left(a,t[i])
    #print(t[i],k)
    if a[k] == t[i] and u[k] == 0 and k < i:
        #print(a[i],t[i],i)
        sum += 1
        u[k] += 1
print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)
t.sort(reverse=True)


u = [0 for i in range(len(t))]

#print(a)        
#print(t)
sum = 0
for i in range (len(a)-1,-1,-1):
    k = bisect_left(a,t[i])
    #print(t[i],k)
    if a[k] == t[i] and u[k] == 0 and k != i:
        #print(a[i],t[i],i)
        sum += 1
        u[k] += 1
print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)
t.reverse()

u = [0 for i in range(len(t))]

#print(a)        
#print(t)
sum = 0
for i in range (len(a)-1,-1,-1):
    k = bisect_left(a,t[i])
    #print(t[i],k)
    if a[k] == t[i] and u[k] == 0 and k != i:
        #print(a[i],t[i],i)
        sum += 1
        u[k] += 1
print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)
t.reverse()
a.sort(reverse=True)

c = {}
for aa in a:
    if aa in c:
        c[aa] += 1
    else:
        c[aa] = 1

#print(t)
#print(a)        
#print(c)

sum = 0
i = 0

for i in range(len(a)-1):

    if t[i] in c :
        #print("\t",a[i],t[i])
        if c[t[i]] > 0 :
            if c[t[i]] == 1 and a[i] == t[i]:
                pass
            else:
                #print("\t",a[i],t[i])                
                sum += 1
                c[t[i]] -= 1
print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)
t.reverse()
a.sort(reverse=True)

c = {}
for aa in a:
    if aa in c:
        c[aa] += 1
    else:
        c[aa] = 1

sum = 0
i = 0

u = [0 for i in range(len(a))]

for i in range(len(a)-1):

    if t[i] in c :
        if c[t[i]] > 0 :
            if c[t[i]] == 1 and a[i] == t[i]:
                pass
            else:
                sum += 1
                c[t[i]] -= 1
        
print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)
t.reverse()
a.sort(reverse=True)

c = {}
for aa in a:
    if aa in c:
        c[aa] += 1
    else:
        c[aa] = 1

sum = 0
i = 0

u = [0 for i in range(len(a))]

for i in range(len(a)-1):

    if u[i] > 0:
        continue

    if t[i] in c :
        if c[t[i]] > 0 :
            sum += 1
            c[t[i]] -= 1
        
print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)
t.reverse()
a.sort(reverse=True)

#print(t,a)
sum = 0
i = 0

u = [0 for i in range(len(a))]

for i in range(len(a)-1):

    if u[i] > 0:
        continue

    first = i+1
    last = len(a)-1
    found = False
 
    while first<=last and not found:
        midpoint = (first + last)//2
        if a[midpoint] == t[i] and u[midpoint] <= 0 and midpoint != i:
            found = True
            sum += 1
            u[midpoint] +=1
        else:
            if t[i] > a[midpoint]:
                last = midpoint-1
            else:
                first = midpoint+1
print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)

t.reverse()
a.sort(reverse=True)

#print(t,a)
sum = 0
i = 0

u = [0 for i in range(len(a))]

for i in range(len(a)-1):

    if u[i] > 0:
        continue

    first = i+1
    last = len(a)-1
    found = False
 
    while first<=last and not found:
        midpoint = (first + last)//2
        if a[midpoint] == t[i] and u[i] <= 0:
            found = True
            sum += 1
            a.pop(midpoint)
            u[i] +=1
        else:
            if t[i] > a[midpoint]:
                last = midpoint-1
            else:
                first = midpoint+1
    
print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)

t.reverse()
a.sort(reverse=True)

#print(t,a)
sum = 0
i = 0

u = [0 for i in range(len(a))]

for i in range(len(a)-1):

    if u[i] > 0:
        continue

    for j in range(i+1,len(a)):
        if a[j] == t[i] and u[j] <= 0:
            sum += 1
            u[j] += 1
    #print(a)
    
print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)

t.reverse()
a.sort(reverse=True)

sum = 0
i = 0

u = [0 for i in range(len(a))]

for i in range(len(a)-1):

    for j in range(i+1,len(a)):
        if a[j] == t[i] and u[j] <= 0:
            sum += 1
            u[j] += 1
    #print(a)
    
print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)

t.reverse()
a.sort(reverse=True)

sum = 0
i = 0

#print(t,a)

while True:
    
    for j in range(i+1,len(a)):
        if a[j] == t[i] :
            sum += 1
            a.pop(j)

    i = i + 1
    if i >= len(a)-1:
        break

print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)

t.reverse()
a.sort(reverse=True)

sum = 0
i = 0

#print(t,a)

while True:
    
    first = i+1
    last = len(a)-1
    found = False

    while first<=last and not found:
        midpoint = (first + last)//2
        if a[midpoint] == t[i] :
            found = True
            sum += 1
            a.pop(midpoint)
            #print(a)
        else:
            if t[i] > a[midpoint]:
                last = midpoint-1
            else:
                first = midpoint+1
            
    i = i + 1
    if i >= len(a)-1:
        break

print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)

t.reverse()
a.sort(reverse=True)

sum = 0
i = 0

#print(t,a)

while True:
    
    first = i+1
    last = len(a)-1
    found = False

    while first<=last and not found:
        midpoint = (first + last)//2
        if a[midpoint] == t[i] :
            found = True
            sum += 1
            a = a[:midpoint]
            a.extend(a[midpoint:])
            #print(a)
        else:
            if t[i] > a[midpoint]:
                last = midpoint-1
            else:
                first = midpoint+1
            
    i = i + 1
    if i >= len(a)-1:
        break

print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
n = int(input())
a = list(map(int,input().split()))
a.sort()
b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

t = []
bIdx = 0
for aa in a :
    while b[bIdx] <= aa:
        bIdx += 1   
    t.append(b[bIdx]-aa)

t.reverse()
a.sort(reverse=True)

sum = 0
i = 0

#print(t,a)

while True:
    
    first = i+1
    last = len(a)-1
    found = False

    while first<=last and not found:
        midpoint = (first + last)//2
        if a[midpoint] == t[i] :
            found = True
            sum += 1
            a = a[:midpoint]
            a.extend(a[midpoint:])
            print(a)
        else:
            if t[i] > a[midpoint]:
                last = midpoint-1
            else:
                first = midpoint+1
            
    i = i + 1
    if i >= len(a)-1:
        break

print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
a = list(map(int,input().split()))
a.sort(reverse=True)
u = [0 for i in range(len(a))]

def binarySearch(alist, item,exhi):
    first = 0
    last = len(alist)-1
    found = False

    while first<=last and not found:
        midpoint = (first + last)//2
        if alist[midpoint] == item and u[midpoint] <= 0 and midpoint != exhi:
            found = True
            u[midpoint] += 1
        else:
            if item > alist[midpoint]:
                last = midpoint-1
            else:
                first = midpoint+1

    return found


b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

sum = 0
i = 0

#print(a)
while True:

    if u[i] > 0:
        i = i + 1
        if i >= len(a)-1:
            break        
        continue

    t = 0
    for bb in b :
        if bb > a[i]:
            t = bb - a[i]
            break
    
    if t > a[i]:
        i = i + 1
        if i >= len(a)-1:
            break
        continue

    if t in a :
        idx = 0
        while True:
            try:
                idx = a.index(t,idx)
                if u[idx] == 0 and idx != i:
                    u[idx] += 1
                    sum += 1
                    break
                elif idx == i:
                    break
            except:
                break
            
    i = i + 1
    if i >= len(a)-1:
        break

print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Runtime Error):
n = int(input())
a = list(map(int,input().split()))
a.sort(reverse=True)

b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 
     67108864, 134217728, 268435456, 536870912]

sum = 0
i = 0
while True:

    t = 0
    for bb in b :
        if bb > a[i]:
            t = bb - a[i]
            break
    #print(t)
    
    for j in range(i,len(a)):
        if a[j] == t:
            sum += 1
            a = a[:j]
            a.extend(a[j+1:])
            #print(a)

    i = i + 1
    if i >= len(a)-1:
        break

print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
a = list(map(int,input().split()))
a.sort(reverse=True)

b = [2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 
     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912]

sum = 0
i = 0
while True:

    t = 0
    for bb in b :
        if bb > a[i]:
            t = bb - a[i]
            break
    
    if a[i+1:].count(t) > 0:
        sum += 1
        a.remove(t)

    i = i + 1
    if i >= len(a):
        break

print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
a = list(map(int,input().split()))

b = []

i = 1
max = 10**9
while True:
    t = 2**i
    if t < max:
        b.append(t)
    else:
        break
    i = i+1

a.sort(reverse=True)
#print(a)

sum = 0
i = 0
while True:

    t = 0
    for bb in b :
        if bb > a[i]:
            t = bb - a[i]
            break
    
    if a[i+1:].count(t) > 0:
        sum += 1
        a.remove(t)

    i = i + 1
    if i >= len(a):
        break

print(sum)

Fixed submission:
from bisect  import bisect_left

n = int(input())
a = list(map(int,input().split()))
a.sort()
#print(a)

sum = 0
for i in range (len(a)-1,-1,-1):

    b = 1
    while b <= a[i]:
        b = b<<1
    t = b - a[i]
    #print("2^",t)

    k = bisect_left(a,t)
    if a[k] == t and k < i:
        sum += 1
        a[k] -= 0.1
        a[i] += 0.1
print(sum)