customize color usercolors theme

I've already read the topic about the customization of colours in beamer (in this forum and on google..) but I didn't find any solution!

My aims is to set the basic colours of the Madrid beamers themes changing from the default blue to the Rgb = {0,120,174} . I thought that was a simple thing but I didn't come out ...

\documentclass{beamer}

\definecolor{beamer@blendedblue}{rgb}{1,0,0}