View Compilation Error

0_0_29549237_30673.cpp: In function 'int main()':
0_0_29549237_30673.cpp:34:21: error: 'h' was not declared in this scope
   scanf("%d%d%d%d",&h,&w,&m,&n);
                     ^
0_0_29549237_30673.cpp:34:24: error: 'w' was not declared in this scope
   scanf("%d%d%d%d",&h,&w,&m,&n);
                        ^
0_0_29549237_30673.cpp:34:27: error: 'm' was not declared in this scope
   scanf("%d%d%d%d",&h,&w,&m,&n);
                           ^
0_0_29549237_30673.cpp:34:30: error: 'n' was not declared in this scope
   scanf("%d%d%d%d",&h,&w,&m,&n);
                              ^