#include <stdio.h>

#include <string.h>

int main()

{

FILE* stream1;

FILE* stream2;

char buffer[100];

char buffer2[100];

int i, j;

int distance;


stream1 = fopen("source.txt", "w");

stream2 = fopen("dest.txt", "w");


fgets(buffer, sizeof(buffer), stdin);

fputs(buffer, stream1);


for (i = 0; i <= strlen(buffer); i++)

{

fseek(stream1, i, SEEK_SET);

distance = ftell(stream1);


if ((distance + 1) % 5 == 0)

{

for (j = distance; j >= distance - 4; j--)

{

fputc(buffer[j], stream2);

}

}

}

fclose(stream1);

fclose(stream2);

return 0;

}