#include <iostream>
using namespace std;

int jz(long long B, long long x) {
	int value = 1, x_B = 0;
	while (x != 0) {
		if ((x % 10) >= B)
			return 2147483647;
		x_B += (x % 10) * value;
		value *= B;
		x /= 10;
	}
	return x_B;
}

int main() {
	long long p, q, r;
	cin >> p >> q >> r;
	for (long long i = 2; i <= 16; i++) {
		if (jz(i, p) == -1 || jz(i, q) == -1 || jz(i, r) == -1)
			continue;
		if (jz(i, p) * jz(i, q) == jz(i, r)) {
			cout << i;
			return 0;
		}
	}
	cout << "0" << endl;
	return 0;
}