Pat grade a 1049 counting ones

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#include<iostream>
#include<vector>
#include<bits/stdc++.h>

using namespace std;

int main(void){
    int i, j, k, m, n, h, mm, nn;
    cin>>m;
    mm = 0;
    string s;
    for(i=1; i<=m; i++){
        s += to_string(i);
    }
    for(i = 0; i < s.length(); i++){
        if(s[i]=='1') mm++;
    }
    cout<<mm;
    return 0;
}

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