#include <stdio.h>
#include <string.h>

int isnum(char c){
	if(c >= '0' && c <= '9') return 1;
	else return 0;
}
long long int exchange(char* str, int r){
	long long int res = 0, weight = 1;
	int i;
	for(i = strlen(str)-1; 0 <= i; i--){
		res += isnum(str[i]) ? (str[i]-'0')*weight : (str[i]-'A'+10)*weight;
		weight*=r;
	}
	return res;
}
int main(void) {
	int n, i;
	long long int min = -1;
	scanf("%d", &n);
	for(i = 0; n > i; i++){
		char str[13];
		int c, max = -1;
		long long int buf;
		scanf("%s", str);
		for(c = 0; strlen(str) > c; c++){
			if(max < str[c]) max = str[c];
		}
		if(isnum(max)) max = max-'0';
		else max = max-'A'+10;
		buf = exchange(str, max+1);
		if(min == -1 || buf < min) min = buf;
	}
	printf("%lld", min);
	return 0;
}