#include <fstream>

using namespace std;

ifstream fin("moretime.in");
ofstream fout("moretime.out");

struct client {
    int adr, val;
} v[10005];

int n, val, adr, t, aux, s[10000];

int main() {
    fin >> n;
    for (int i = 1; i <= n; i++) {
        fin >> adr >> val;
        aux = adr;
        while (aux > 9)
            aux /= 10;
        if (aux == adr % 10) {
            t++;
            v[t].adr = adr;
            v[t].val = val;
        }
    }
    fout << t << endl;
    for (int i = 1; i <= t; i++) {
        s[i] = s[i - 1] + v[i].val;
        s[i] = s[i] % t;
    }
    for (int i = 1; i <= t; i++)
    if (s[i] == 0) {
        fout << i;
        for (int k = 1; k <= i; k++)
            fout << v[k].adr << " ";
        return 0;
    }
    for (int i = 1; i < t; i++)
        for (int j = i + 1; j <= t; j++)
            if (s[i] == s[j]) {
                fout << j - i << endl;
                for ( int k = i + 1; k <= j; k++)
                    fout << v[k].adr << " ";
                return 0;
            }
}