977A - Wrong Subtraction.cpp

#include <iostream>

int main()
{
    int n,k;
    std::cin >> n >> k;
    
    int r;
    for(int i = 0; i < k; i++)
    {
        r = n % 10;
        if(r == 0)
        {
            n = n / 10;
        } else
        {
            n = n - 1;
        }
    }
    std::cout << n << "\n";
    std::cin.get();
}