AOJ 0002 http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=0002&lang=jp

aoj_0002.cpp

#include<iostream>

using namespace std;

int main() {
  int i, j;
  while(cin >> i >> j) {
    int sum = i + j;
    int count = 0;
    while(sum > 0) {
      sum /= 10;
      count++;
    }
    cout << count << endl;
  }
}