PROGRAM fuct
IMPLICIT NONE
INTEGER::n,i,k
READ*,n
k=0
DO i=1,n
IF (MOD(n,i)==0) THEN
k=k+1
END IF
END DO
IF (k==2) THEN
PRINT*,"yes"
ELSE
PRINT*,"no"
END IF
END
PROGRAM fuct
IMPLICIT NONE
INTEGER::n,i,k
READ*,n
k=0
DO i=1,n
IF (MOD(n,i)==0) THEN
k=k+1
END IF
END DO
IF (k==2) THEN
PRINT*,"yes"
ELSE
PRINT*,"no"
END IF
END