foo.c: In function 'main':
foo.c:24:18: warning: format '%d' expects argument of type 'int', but argument 2 has type 'long long int' [-Wformat=]
         printf("%d",ans);
                 ~^
                 %lld
foo.c:14:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld%lld%lld%lld%lld",&x,&y,&n,&m,&l);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.c:17:19: warning: 'len1' may be used uninitialized in this function [-Wmaybe-uninitialized]
     if (gcd(l,len)%gcd(l,len1)!=0) printf("Impossible");else{
         ~~~~~~~~~~^~~~~~~~~~~~

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。