#include <stdio.h>
int change(char str_input[], char str_result[],char str_temp[])
{
   unsigned int x;
   int lenx,cntto3;
   while(lenx>0)
    {

        if (cntto3<=3){
            sprintf(str_result,"%c%s",str_input[lenx-1],str_temp);
            cntto3++;
            lenx--;
        } else{
            sprintf(str_result," %s",str_temp);
            cntto3=1;
        }
        sprintf(str_temp,"%s",str_result);
    }
}
int main()
{
    unsigned int x;
    char input[255];
    char result[255];
    char temp[255];
    int lenx,cntto3;
    printf("Enter natral value - ");
    scanf("%u",&x);
    lenx=sprintf(input,"%u",x);
    cntto3=1;
    sprintf(temp,"");
    change(input,result,temp);
    printf("Result=%s\n",result);
    return 0;
}