./Main.c:1:1: warning: data definition has no type or storage class
c,i,k[30],x;main(n){for(;~scanf("%d",&i);)k[__builtin_ctz(i)]=--n&&(x^=i);for(i=30;i--;x&n&&(c++,x=~x&n-1))n=k[i]<<i;printf("%d",x?-1:c);}
^
./Main.c:1:1: warning: type defaults to ‘int’ in declaration of ‘c’ [-Wimplicit-int]
./Main.c:1:3: warning: type defaults to ‘int’ in declaration of ‘i’ [-Wimplicit-int]
c,i,k[30],x;main(n){for(;~scanf("%d",&i);)k[__builtin_ctz(i)]=--n&&(x^=i);for(i=30;i--;x&n&&(c++,x=~x&n-1))n=k[i]<<i;printf("%d",x?-1:c);}
^
./Main.c:1:5: warning: type defaults to ‘int’ in declaration of ‘k’ [-Wimplicit-int]
c,i,k[30],x;main(n){for(;~scanf("%d",&i);)k[__builtin_ctz(i)]=--n&&(x^=i);for(i=30;i--;x&n&&(c++,x=~x&n-1))n=k[i]<<i;printf("%d",x?-1:c);}
^
./Main.c:1:11: warning: type defaults to ‘int’ in declaration of ‘x’ [-Wimplicit-int]
c,i,k[30],x;main(n){for(;~scanf("%d",&i);)k[__builtin_ctz(i)]=--n&&(x^=i);for(i=30;i--;x&n&&(c++,x=~x&n-1))n=k[i]<<i;printf("%d",x?-1:c);}
^
./Main.c:1:13: warning: ret...