#include <stdio.h>

int main(void) {  

  int a = 5, b = 7, c;

  c = a + b;

  { 
    int b = 10, c;

    {
      int a = 3, c;
      c = a + b;  
      printf("Inner:  a + b = %d + %d = %d\n", a, b, c);
    }

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

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