Compilare: main.cpp:2:91: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] int n,m;long long rez;int cmmdc(int a,int b){int r;while(b){r=a%b;a=b;b=r;}return a;}main(){int i,j;freopen("paralelograme.in","r",stdin);freopen("paralelograme.out","w",stdout);scanf("%d%d",&n,&m);for(i=1;i<=n;i++)for(j=1;j<=m;j++)rez+=1LL*((i-1)*(j-1)+i*j+i+j-cmmdc(i,j)-1)*(n-i+1)*(m-j+1);printf("%lld\n",rez);} ^ main.cpp: In function 'int main()': main.cpp:2:138: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] int n,m;long long rez;int cmmdc(int a,int b){int r;while(b){r=a%b;a=b;b=r;}return a;}main(){int i,j;freopen("paralelograme.in","r",stdin);freopen("paralelograme.out","w",stdout);scanf("%d%d",&n,&m);for(i=1;i<=n;i++)for(j=1;j<=m;j++)rez+=1LL*((i-1)*(j-1)+i*j+i+j-cmmdc(i,j)-1)*(n-i+1)*(m-j+1);printf("%lld\n",rez);} ^ main.cpp:2:178: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] int n,m;long long rez;int cmmdc(int a,int b){int r;while(b){r=a%b;a=b;b=r;}return a;}main(){int i,j;freopen("paralelograme.in","r",stdin);freopen("paralelograme.out","w",stdout);scanf("%d%d",&n,&m);for(i=1;i<=n;i++)for(j=1;j<=m;j++)rez+=1LL*((i-1)*(j-1)+i*j+i+j-cmmdc(i,j)-1)*(n-i+1)*(m-j+1);printf("%lld\n",rez);} ^ main.cpp:2:198: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] int n,m;long long rez;int cmmdc(int a,int b){int r;while(b){r=a%b;a=b;b=r;}return a;}main(){int i,j;freopen("paralelograme.in","r",stdin);freopen("paralelograme.out","w",stdout);scanf("%d%d",&n,&m);for(i=1;i<=n;i++)for(j=1;j<=m;j++)rez+=1LL*((i-1)*(j-1)+i*j+i+j-cmmdc(i,j)-1)*(n-i+1)*(m-j+1);printf("%lld\n",rez);} ^