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

int main(void){
    int i,n;
    char *buf,*out;
    *buf=NULL;
    *out=NULL;
    n=getchar();
    for(i=0;i<n;i++){
        scanf("%s",buf);
        strcat(out,buf);
        *buf=NULL;
    }
    puts(out);

    return 0;
}