foo.cc: In function 'int main()':
foo.cc:5:9: warning: unused variable 'a' [-Wunused-variable]
    5 | int n,m,a,b,c,s1,s2,s3,i;
      |         ^
foo.cc:5:11: warning: unused variable 'b' [-Wunused-variable]
    5 | int n,m,a,b,c,s1,s2,s3,i;
      |           ^
foo.cc:5:13: warning: unused variable 'c' [-Wunused-variable]
    5 | int n,m,a,b,c,s1,s2,s3,i;
      |             ^
foo.cc:5:18: warning: variable 's2' set but not used [-Wunused-but-set-variable]
    5 | int n,m,a,b,c,s1,s2,s3,i;
      |                  ^~
foo.cc:5:21: warning: variable 's3' set but not used [-Wunused-but-set-variable]
    5 | int n,m,a,b,c,s1,s2,s3,i;
      |                     ^~

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