\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
-\usepackage{newtxtext}
-\usepackage[cmintegrals]{newtxmath}
-%\usepackage{mathptmx,helvet,courier}
+%\usepackage{newtxtext}
+%\usepackage[cmintegrals]{newtxmath}
+\usepackage{mathptmx,helvet,courier}
\usepackage{amsmath}
\usepackage{graphicx}