The output from LPSolver is not the optimal result - r

Question

Since I need to create an automatic shift planning tool, R lpSolve is the package I plan to use. However, I can't get the optimal output by the code shown as below. The output(hourly supply by accumulating all shifts available) can't fulfill the demand. e.g. The demand for a hour is 46 but the supply is only 25 which means 21 unit of demand can't be satisfied.
Background:
The objective
To minimize the difference between total supply and total demand.
To minimize the difference between supply and demand for each hour.
Constraint
Shift constraint - each hour might have several shifts available to be assigned.
Max capacity - I have the cap of supply. the sum of total shift cant exceed the cap for each hour. (46 is the cap in this example).
In the constr matrix, 24 rows represent 24 hours starting from 7 am and 9 columns refers to no. of shifts I have.
The constr.val refers to hourly demand.
Please let me know if there is anything unclear. thanks!
library(lpSolve)
obj.fun<-c(1,1,1,1,1,1,1,1,1)
constr<-matrix(c(
1, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 0, 0, 0, 0, 0, 0,
1, 0, 0, 1, 0, 0, 0, 0, 0,
1, 0, 0, 1, 0, 1, 0, 0, 0,
1, 0, 0, 1, 0, 1, 0, 1, 0,
1, 0, 0, 1, 0, 1, 0, 1, 0,
1, 0, 0, 1, 0, 1, 0, 1, 0,
0, 1, 0, 1, 0, 1, 0, 1, 0,
0, 1, 0, 1, 0, 1, 0, 1, 0,
0, 1, 0, 1, 0, 1, 0, 1, 0,
0, 1, 0, 0, 1, 1, 0, 1, 0,
0, 1, 0, 0, 1, 0, 1, 1, 0,
0, 1, 0, 0, 1, 0, 1, 0, 1,
0, 1, 0, 0, 1, 0, 1, 0, 1,
0, 1, 0, 0, 1, 0, 1, 0, 1,
0, 0, 1, 0, 1, 0, 1, 0, 1,
0, 0, 1, 0, 1, 0, 1, 0, 1,
0, 0, 1, 0, 1, 0, 1, 0, 1,
0, 0, 1, 0, 0, 0, 1, 0, 1,
0, 0, 1, 0, 0, 0, 0, 0, 1,
0, 0, 1, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0), nrow = 24, byrow = TRUE)
constr.dir <- rep("<=", 24)
constr.val <- c(24, 20, 21, 22, 26, 34, 40, 44,
46, 46, 46, 46, 46, 46, 46, 46,
46, 46, 46, 46, 46, 46, 41, 27)
day.shift <- lp("max", obj.fun, constr, constr.dir,
constr.val, compute.sens = TRUE)
day.shift$solution