#include<stdio.h>
int main(){
    int n;
    if(scanf("%d",&n) != 1){
        printf("Invalid input\n");
        return 1;
    }
    if (n <= 1|| n > 15){
        printf("Invalid input\n");
        return 1;
    }
    int weights;
    for (int i = 0; i < n; i++){
        if (scanf("%d", &weights[i]) != 1){
            printf("Invalid input\n");
            return 1;
        }
    }
        for (int i = 0; i < n; i++){
            printf("%d", weights[i]);
        }
        printf("\n");
        return 0;
    }