Rowing Intervals Workout

For time:
3 rounds of:
20/16cal Row
Rest 1min btw rounds
-- then --
2 rounds of:
30/24cal Row
Rest 1:30
-- then --
1 rounds of:
40/32cal Row
Rest 2min
-- then --
2 rounds of:
30/24cal Row
Rest 1:30
-- then --
3 rounds of:
20/16cal Row
Rest 1min