Eddie, Rose, Jack and Mary are being chased by robbers to the riverside at night. They only have one flashlight.~~Along the river, there is a bridge that can only allow $2$ people to crosss at one time. Eddie takes $1$ minutes to cross the bridge, Jack takes $2$ minutes, Rose takes $5$ minutes and Mary takes $10$ minutes. What is the shortest amount of time needed for all $4$ of them to cross the bridge? 
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