#include <bits/stdc++.h>   using namespace std;   void solve() {     long long N, K;     string X;     cin >> N >> K;     cin >> X;     string foo = X;     for (long long i = 0; i + K < foo.size(); i++) {       foo[i + K] = foo[i];     }     if (foo >= X) {       cout << foo.size() << endl;       cout << foo << endl;       return;     }     string bar = foo.substr(0, K);     bool all_nine = true;     for (auto it : bar)       if (it !=  9 ) {         all_nine = false;         break;       }     if (all_nine) {       cout << N + 1 << endl;       for (long long i = 0; i < (N + 1); i++) {         if (i % K == 0)           cout << 1;         else           cout << 0;       }       cout << endl;       return;     }     for (long long i = 0; i < (bar.size()); i++) {       if (bar[bar.size() - i - 1] ==  9 ) {         bar[bar.size() - i - 1] =  0 ;       } else {         bar[bar.size() - i - 1] += 1;         break;       }     }     cout << N << endl;     ;     for (long long i = 0; i < (N); i++) cout << bar[i % K];     cout << endl;   }   int main(void) {     cin.tie(0);     ios::sync_with_stdio(false);     cout.precision(12);     cout << fixed;     solve();     return 0;   }   