PROGRAM ex4_4 
IMPLICIT NONE 
INTEGER:: year, days 
PRINT *, 'Input a year:' 
READ *, year 
days = 365 * year + year / 4 - year / 100 + year / 400 
IF(MOD(days,7)==1)THEN
PRINT *,'月曜日'
ELSE IF(MOD(days,7)==2)THEN
PRINT *,'火曜日'
ELSE IF(MOD(days,7)==3)THEN
PRINT *,'水曜日'
ELSE IF(MOD(days,7)==4)THEN
PRINT *,'木曜日'
ELSE IF(MOD(days,7)==5)THEN
PRINT *,'金曜日'
ELSE IF(MOD(days,7)==6)THEN
PRINT *,'土曜日'
ELSE IF(MOD(days,7)==0)THEN
PRINT *,'日曜日'
END IF
END PROGRAM ex4_4