def judge(x):
    if x%T==0:
        return x//T*(T-1)+1<=(1+P)*V
    else:
        return x//T*(T-1)+x%T<=(1+P)*V

def binary_search():
    l, r = 0, 10**20
    
    while l<=r:
        m = (l+r)//2
        
        if judge(m):
            l = m+1
        else:
            r = m-1
    
    return r

V, T, P = map(int, input().split())
print(binary_search()+1)