479A. Wrong Subtraction.cpp

#include<bits/stdc++.h>
using namespace std;
int main()
{
    long long int a,b,i;
    cin>>a>>b;
    for(i=0;i<b;i++)
    {
        if(a%10==0)
        {
            a=a/10;
        }
        else
        {
            a=a-1;
        }
    }
    cout<<a<<endl;
}