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

#define MAX    250

long i,j,iLength,iBlock,iPos;
char pszText[MAX+1], pszEncrypted[MAX+1];

int main(void) {
   scanf("%ld %s", &iBlock, pszEncrypted);
   iLength= strlen(pszEncrypted);
   j= 0; iPos= 0;
   for (i= 0; i< iLength; i++) {
       pszText[iPos]= pszEncrypted[i];
       iPos= (iPos+iBlock<iLength) ? (iPos+iBlock) : (++j);
   }
   printf("%s\n",pszText);

   return(0);
}