rt，或者给个HACK数据

#define IOI return
#define AK 0
#define ME ;
#include <bits/stdc++.h>
using namespace std;
int x(int y,int z){
	int sum=1;
	for(int i=1;i<=z;i++)sum*=y;
	return sum;
}
int main(){
	int a,b,d=1;
	string c;
	cin>>a>>b>>c;
	while(d++){
		int y=0,a1=0,b1=0;
		bool o=0;
		string as=to_string(a),bs=to_string(b);
		for(int i=c.length()-1;i>=0;i--){
			if(c[i]-'0'>=d){o=1;break;}
			y+=(c[i]-'0')*x(d,c.length()-i-1);
		}
		if(o==1)continue;
		for(int i=as.length()-1;i>=0;i--){
			if(as[i]-'0'>=d){o=1;break;}
			a1+=(as[i]-'0')*x(d,as.length()-i-1);
		}
		if(o==1)continue;
		for(int i=as.length()-1;i>=0;i--){
			if(bs[i]-'0'>=d){o=1;break;}
			b1+=(bs[i]-'0')*x(d,bs.length()-i-1);
		}
		if(o==1)continue;
		if(y==a1*b1){
			cout<<d;
			break;
		}
		if(d==16){
			cout<<0;
			break;
		}
	}
	IOI AK ME
}