#include<stdio.h>

int main(){
    int size,ind;
    scanf("%d",&size);
    if(size<0){
        printf("Invalid input");
        return 0;
    }
    int arr[size];
    for(ind=0;ind<size;scanf("%d",arr[ind++]));
    for(ind =0;ind<size-1;ind++){
        if(arr[ind]!=NULL){
            printf("%d",arr[ind]);
        }
    }
    return 0;
}