Why do I receive an "Expected expression" error at every "else"?

This algorithm must print four numbers in crescent order. When I start it, I receive an error: "Expected expression". Why does this happen?

#include <stdio.h>

int main()
{
    int A,B,C,D,Riserva;

    scanf("%d",&A);
    scanf("%d",&B);
    scanf("%d",&C);
    scanf("%d",&D);

    if(A>B)
    else
    {
        Riserva=A;
        A=B;
        B=Riserva;
    }
    if(C>D)
    else
    {
        Riserva=C;
        C=D;
        D=Riserva;
    }
    /*Fine*/
    if(A>C)
        else
        {
            Riserva=A;
            A=C;
            C=Riserva;
        }
    if(B>D)
        else
        {
            Riserva=B;
            B=D;
            D=Riserva;
        }
    /*Fine*/
    if(A>D)
        else
        {
            Riserva=A;
            A=D;
            D=Riserva;
        }
    if(B>C)
        else
        {
            Riserva=B;
            B=C;
            C=Riserva;
        }

    printf("\n\n%d %d %d %d",D,C,B,A);

}