백준 10156 python

def findAnswer(K, N, M):
    sum = K * N

    if(sum <= M):
        answer = 0
    else:
        answer = sum - M

    return answer

# K = int(input())
# N = int(input())
# M = int(input())
K, N, M = map(int, input().split())

print(findAnswer(K, N, M))