! 成績チェック
! 固定形式
      PROGRAM ex3_1

        INTEGER :: n, s, k

        s = 0
        k = 0

   10   PRINT *, 'Input mark of each student ( quit if negative ) : '
        READ *, n

        IF ( n < 0 ) GOTO 999
        s = s + 1
        IF ( n >= 60 ) k = k + 1
        GOTO 10

  999   PRINT *, k, ' students cleared this exam. total = ', s

      END PROGRAM ex3_1