import sys
sys.setrecursionlimit(10000000)
MOD = 10 ** 9 + 7
INF = 10 ** 15

def main():
    V,T,P = map(int,input().split())

    l = 0
    r = 10 ** 20
    while r - l > 1:
        mid = (r + l)//2
        if (mid - P*V - V)*T + 1 <= mid:
            l = mid
        else:
            r = mid
    print(r)
if __name__ == '__main__':
    main()