program loop
integer row, col
integer mat(2,2)
integer sum
mat (1, 1) = 1
mat (1, 2) = 2
mat (2, 1) = 3
mat (2, 2) = 4
sum = 0
Do row = 0, col, 1
Do col = 0, row, 1
sum = mat(row, col)
End Do
End Do
print *, sum
end program loop
cHJvZ3JhbSBsb29wCiAgICAgIGludGVnZXIgcm93LCBjb2wKICAgICAgaW50ZWdlciBtYXQoMiwyKQogICAgICBpbnRlZ2VyIHN1bQogICAgICBtYXQgKDEsIDEpID0gMQogICAgICBtYXQgKDEsIDIpID0gMgogICAgICBtYXQgKDIsIDEpID0gMwoJIG1hdCAoMiwgMikgPSA0CiAgICAgc3VtID0gMAogICAgICBEbyByb3cgPSAwLCBjb2wsIDEKIAkgICAgRG8gY29sID0gMCwgcm93LCAxCiAJICAgIHN1bSA9IG1hdChyb3csIGNvbCkKIAkgICAgRW5kIERvCiAgICAgIEVuZCBEbwoKICAgICAgcHJpbnQgKiwgc3VtCgkgCmVuZCBwcm9ncmFtIGxvb3A=