#include<bits/stdc++.h> using namespace std; int Change(char *x,int b) { int num = 0; for(int i = 0; i < strlen(x); i++) { if(x[i] - '0' >= b) return -1; num = num * b + x[i] - '0'; } return num; } int main() { char p[9], q[9], r[9]; cin >> p >> q >> r; int B = 0; for(int i = 2; i <= 16; i++) { if(cha(p, i) == -1 || cha(q, i) == -1 || cha(r, i) == -1) continue; if(cha(p, i) * cha(q, i) == cha(r, i)) { B = i; break; } } cout << B << endl; return 0; }