!-----  Ex5_6: Prime Number upto 100   -----
      INTEGER :: n, m, max=100
      PRINT *, 2
 xxx: DO n = 3, max, 2
         DO m = 3, SQRT(REAL(n)), 2
            IF( MOD(n,m)==0 ) CYCLE xxx
         END DO
            PRINT *, n
      END DO xxx
      END