foo.c: In function 'main':
foo.c:5:13: warning: format '%d' expects argument of type 'int *', but argument 2 has type 'long long int *' [-Wformat=]
     scanf("%d %d %d %d",&a,&b,&c,&d);
            ~^           ~~
            %lld
foo.c:5:16: warning: format '%d' expects argument of type 'int *', but argument 3 has type 'long long int *' [-Wformat=]
     scanf("%d %d %d %d",&a,&b,&c,&d);
               ~^           ~~
               %lld
foo.c:5:19: warning: format '%d' expects argument of type 'int *', but argument 4 has type 'long long int *' [-Wformat=]
     scanf("%d %d %d %d",&a,&b,&c,&d);
                  ~^           ~~
                  %lld
foo.c:5:22: warning: format '%d' expects argument of type 'int *', but argument 5 has type 'long long int *' [-Wformat=]
     scanf("%d %d %d %d",&a,&b,&c,&d);
                     ~^           ~~
                     %lld
foo.c:6:14: warning: format '%d' expects argument of type 'int', but argument 2 has type 'long long int' [-Wformat=]
     printf("%d",(a*d-b*c)%(1000000000+7));
             ~^  ~~~~~~~~~~~~~~~~~~~~~~~~
             %lld
foo.c:5:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d %d",&a,&b,&c,&d);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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