A portfolio consists of $3$ securities $1,2$ and $3.$ The proportion of these securities is $0\mathrm{.}3,0\mathrm{.}5$ and $0\mathrm{.}2.$ The standard deviation of returns on these securities is $6,9$ and $10$ respectively. The corelation coefficient among security are $1$ and $2=0\mathrm{.}4,1$ and $3=0\mathrm{.}6$ and $2$ and $3=0\mathrm{.}7.$ What is standard deviation of portfolio return?