#include <stdio.h>

int main(void) {  

  int a = 5, b = 7, c;

  c = a + b;

  { 
    int a = 15, b = 17, c;

    {
      int a = 25, b = 27, c;
      c = a + b;  
      printf("Inner: c er %d\n", c);
    }

    c = a + b;  
    printf("Middle: c er %d\n", c);
  }   

  c = a + b;  
  printf("Outer: c er %d\n", c);
  
  return 0;
}